EDdS. 


GENERAL   PSYCHOLOGY 
IN  TERMS  OF  BEHAVIOR 


'GENERAL    PSYCHOLOGY 
IN  TERMS  OF  BEHAVIOR 


BY 
STEVENSON  SMITH,  Ph.D. 

PROFESSOR    OF    PSYCHOLOGY    IN    THE    UNIVERSITY    OF    WASHINGTON 

AND 

EDWIN  R.  GUTHRIE,  Ph.D. 

ASSISTANT    PROFESSOR    OF    PSYCHOLOGY    IN    THE    UNIVERSITY    OF    WASHINGTON 


D.  APPLETON  AND  COMPANY 

NEW  YORK  LONDON 

1921 


EDflfc. 

PSYCH. 

LIBfiAfir 


COPYRIGHT,    1921,    BT 

D.    APPLETON  AND  COMPANY 


PRINTED    IN    THE    1'HITFD    STATFS    OF    AUFRICA 


PREFACE 

In  this  book  an  attempt  is  made  to  state  in  terms  of 
behavior  the  facts  and  principles  of  general  psychology. 
Although  the  field  it  covers  is  somewhat  more  extended 
than  that  of  most  text-books  in  psychology,  the  authors 
have  sought  to  make  the  book  compact  as  well  as  sys- 
tematic. For  efficiency  of  teaching  much  traditional 
but  unnecessary  detail  has  been  omitted.  Only  such 
facts  of  physiology  as  have  important  significance  in  an 
introductory  course  are  included.  Many  blind-alley 
topics,  an  acquaintance  with  which  has  been  considered 
a  polite  accomplishment  in  psychology,  have  been  de- 
liberately disregarded.  The  facts  set  forth  are  those 
which  lead  the  student  to  a  systematic  explanation  of 
his  own  conduct  and  that  of  his  fellows.  The  purpose 
of  the  book  is  to  describe  man's  original  nature,  the 
way  in  which  this  nature  is  altered  by  use,  and  the  com- 
mon modes  of  individual  and  social  behavior  that  result. 

S.  S. 

E.  R.  G. 


I 


CONTENTS 

PAGE 

Preface  v 

CHAPTER 

I.  The  Elements  of  Behavior 1 

Behavior  Dependent  on  Bodily  Structure  ...  3 

Classes  of  Sense  Organs 0 

The  Exteroeeptors 7 

The  Interoceptors 20 

The  Proprioceptors 21 

The  Nervous  System 23 

Regulatory  Character  of  Responses       ....  28 

Delayed  Utility  of  Responses 31 

Apparent  Absence  of  Utility  of  Some  Responses       .  32 

Orientation,  Locomotion,  and  Intervention  ...  33 

Internal   Responses 36 

The  Action  of  a  Stimulus-Response  Mechanism  .        .  39 

Weber's  Law 42 

The  Interaction  of  Stimulus-Response  Mechanisms  .  43 

Compromise  Responses 46 

II.  Instinct 48 

Reflexes 49 

Instincts  Are  Chain  Reflexes 54 

Precurrent  and  Consummatory  Responses    ...  60 
The  Effect  of  Varying  Situations  upon  Precurrent 

Responses 67 

Individual  Differences 70 

III.  Learning 75 

Positive  Adaptation 76 

Negative  Adaptation 80 

Transitory    Changes   of    Threshold   during   a    Single 

Practice  Period 85 

Initial  Torpor  and  Fatigue 85 

The  Conditioned  Response 88 

Conditioned  Emotional  Responses 91 

The  Substitution  of  Similar  Stimuli      ....  94 

Facilitating  Effect  of  Conditioning  Stimuli  ...  95 
vii 


viii  CONTENTS 

CHAPTER  PAGE 

The  Neural  Basis  of  Learning 97 

Associative  Inhibition 99 

The  Serial  Response 100 

The  Effects  of  Practice  on  the  Serial  Response  .        .105 

Forgetting 109 

Whole  and  Part  Learning 113 

Results  of  the  Distribution  of  Practice       .       .        .  115 

Learning  Meaningful  Material 116 

Trial  and  Error 117 

The  Shortening  of  a  Trial  and  Error  Series  into  a 

Final  Habit  Response 119 

Imitation 130 

IV.  CcENOTROPES 134 

Common  Habits 138 

Both  Instincts  and  Coenotropes  Are  Common  Modes 

of  Behavior 145 

Play 148 

Other  Examples  of  Common  Modes  of  Behavior        .  153 

V.  Perception 158 

Perception  and  Speech 162 

At  Different  Times  a  Situation  May  Prompt  Us  to 

Different  Perceptions 166 

Compromise  Responses  in  Perception  ....  170 

Perceptions  from  Simultaneous  Stimuli        .       .        .  171 

Space  Perception 172 

Visual  Space  Perception 173 

Visual  Perception  of  Objects 178 

Auditory  Space  Perception 180 

Auditory  Perception  of  Objects 181 

Olfactory  Perception 183 

Kinesthetic  and  Static  Perception        ....  186 

Touch  Perception 186 

Time  Perception 187 

Judgment 190 

Conviction  and  Belief 195 

VI.  Human  Motives 198 

The  Delayed  Reaction 198 

The  Wish 203 

Attention 204 

Volition 205 

Intention 209 

Drive 210 


CONTENTS  ix 

CHAPTER  PAQB 

Sublimation 214 

Conflict 216 

Over-correction 218 

VII.    Social  Psychology 220 

Fellow  Man  as  a  Constant  Situation     ....  220 

Other  Prevalent  Situations 221 

Formation  of  Habits  in  Common 224 

The  Spread  of  Tradition 232 

Opinion  Spreads  from  Mouth  to  Mouth       .        .       .  236 

Human  Institutions 237 

APPENDIX 

Consciousness      .             243 

Consciousness  and  the  Nervous  System        .       .       .  245 

Sensation 245 

Emotion  and  Affection 250 

Images 250 

Association  of  Ideas 252 

Imagination 255 

Attention 256 

Perception 257 

The  Unconscious 258 

Bibliography 261 

Index 265 


ILLUSTRATIONS 

FIUl'RB  FAQB 

1.  Schematic  Diagram  of  a  Section  through  the  Eye       .         9 

2.  Diagram  of  the  Position  of  the  External  Muscles  That 

Move  the  Eyeball 10 

3.  Schematic   Representation   of   a   Section   through   the 

Retina,  Showing  the  Position  of  Rods  and  Cones, 
the  Layer  of  Connecting  Neurones,  and  the  Direc- 
tion of  Fibers  of  the  Optic  Nerve     ....       13 

4.  Drawing  from  a   Model  of  the  Inner  Ear,   Showing 

the  Cochlea,  in  Which  Are  the  Sense  Organs  of 
Hearing;  the  Utricle  and  Saccule,  the  Organs  of 
Static  Sense;  and  the  Semi-circular  Canals  .        .       15 

5.  Schematic   Section   through   One  of  the   Coils  of  the 

Cochlea,  Showing  the  Basilar  Membrane  and  Ad- 
jacent Structures 16 

6.  Section  through  the  Olfactory  Membrane  Showing  Ol- 

factory Cells  and  Supporting  Cells  ....       17 

7.  Touch  Corpuscle  from  the  Palm  of  the  Human  Finger      18 

8.  The  Relation  of  Efferent  Fibers  of  the  Autonomic  and 

the  Peripheral   Nervous   Systems  to  the   Central 

Nervous   System 24 

Schematic  Section  of  the  Spinal  Cord  ....  25 
Schematic  Representation  of  Sensory  Neurone  .  .  26 
Schematic  Representation  of  Motor  Neurone  ...  27 
Scheme  of  Nem-al  Pathways  from  a  Sense  Organ  in  the 

Skin  to  a  Muscle 29 

Diagrammatic    Representation    of    the    Chain    Reflex 

Mechanism 56 

Distribution  of  Unselected  Group  of  Runners  .  .  71 
Surface  of  Frequency  Showing  the  Distribution  of  the 

Runners  of  Figure  14  According  to  their  Time  in 

Seconds 71 

Distribution  of  Alpha  Test  Scores  for  College  Students 

and  for  the  Draft  Army 73 

xi 


xii  ILLUSTRATIONS 

FIOl'RB  PAOE 

17.     Distribution  of  Alpha  Test  Scores  for  Various  Groups 

in  the  Draft  Army 73 

19.     Curve  of  Practice  in  Mirror  Drawing       ....       78 

19.  Distribution  of  German  Industrial  Accidents  through- 

out   the    Working    Day,    in    Part    the    Result    of 
Fatigue 87 

20.  Establishing  a  Conditioned  Response       ....       98 

21.  Diagrammatic  Representation  of  the  Formation  of  a 

Serial-Response  Habit 104 

22.  The  Number  of  Repetitions  Required  for  Establishing 

Serial  Responses  of  Various  Lengths       .        .        .     106 

23.  The  Actual  Amount  of  Work  Done  in  Order  to  Learn 

the  Series  of  Various  Lengths 107 

24.  The  Time  Saved  in  Relearning  a  Serial  Response  of  16 

Nonsense  Syllables  Shown  as  a  Function  of  the 
Amount  of  Yesterday's  Practice         ....     110 

25.  The  Rate  of  Forgetting  a  Nonsense  Series      .        .       .     Ill 

26.  Staircase  Figure 168 

27.  The  Cube  Face  that  is  Perceived  as  Nearest  the  Ob- 

server may  also  be  Perceived  as  the  Most  Distant  .     169 

28.  A  Pear  is  Perceived  as  behind  an  Apple  because  it  is 

Partially  Hidden  by  the  Apple 176 

29.  Objects  Higher  in  the  Field  of  Vision  tend  to  be  Per- 

ceived as  More  Distant 177 

30.  Respiratory  Antecedents  of  Voluntary  Movement  .        .     208 


GENERAL   PSYCHOLOGY 
IN  TERMS  OF  BEHAVIOR 


GENERAL  PSYCHOLOGY 

IN   TERMS    OF    BEHAVIOR 


CHAPTER  I 


THE   ELEMENTS   OF   BEHAVIOR 


Psychology  takes  the  common  sense  view  that  any 
animal  is  a  physical  object  in  a  world  of  physical 
objects.  It  assumes  that  all  these  objects  act  upon 
each  other  in  the  ways  described  by  physics,  chem- 
istry, and  physiology.  It  considers  man's  behavior 
as  a  physical  event  that  can  be  analyzed  into  bodily 
movements.  In  this  sense  man's  behavior  is  me- 
chanical and  his  body  is  a  machine. 

The  behavior  of  animals  does  not  involve  new  and 
mysterious  forces  lacking  elsewhere  in  nature,  even 
though  it  is  true  that  an  animal's  structure  is  too 
complex  to  be  duplicated,  and  though  any  attempt 
to  construct  a  machine  that  would  respond  as  elab- 
orately and  appropriately  as  do  animals  to  the  world 
of  surrounding  objects  must  certainly  fail. 

It  must  not  be  supposed  that  thinking  is  denied 
by  physiological  psychology,  A  behavioristic  de- 
scription of  man's  mind  in  no  way  contradicts  the 
common  sense  assumption  that  men  are  conscious. 
We  shall  first  find  out  what  man  does,  and  under 


* 


2  GENERAL  PSYCHOLOGY 

what  circumstances  he  does  it,  because  this  is  open 
to  observation  and  may  be  stated  exactly.1  An  un- 
derstanding of  behavior  is  essential  to  an  under- 
standing of  consciousness. 

All  that  we  can  observe  in  our  fellow  man  is  his 
behavior.  He  moves  his  body  and  its  appendages 
as  he  goes  from  place  to  place  or  as  he  rearranges 
the  objects  about  him.  In  conversation  he  contracts 
the  necessary  muscles  and  is  heard  to  speak.  In 
emotional  expression  he  blushes,  his  pulse  is  altered, 
his  hands  grow  cold,  his  liver  gives  up  its  sugar, 
and  we  see  shame,  anxiety,  or  anger.  His  thoughts, 
as  such,  are  known  to  no  one  but  himself. 

Any  physical  object  is  at  all  times  being  acted 
upon  by  forces  that  affect  it  in  various  ways.  The 
stone  lying  in  the  road  is  moved  about  by  the  im- 
pact of  rain,  warmed  and  expanded  by  the  sun,  and 
scratched  by  the  wheels  of  passing  vehicles.  Its 
responses  to  these  forces  are  simple  and  easily  pre- 
dicted because  of  the  simplicity  of  its  structure. 

If  we  consider  not  only  the  stone  in  the  road  but 
also  the  gopher  who  sits  beside  it,  we  find  the  same 
forces  acting.  The  light  reflected  from  surrounding 
objects  falls  on  both  alike,  both  are  struck  by  the 
rain  or  warmed  by  the  sun,  but  the  result  of  the 
action  of  these  forces  on  the  gopher  is  behavior  quite 

iThe  first  systematic  statement  that  mind  could  be  described  in 
terms  of  behavior  was  made  by  Dr.  E.  A.  Singer,  Jr.,  in  1911.  See 
articles:      "Mind  as  an  Observable  Object,"  Journal  of  Philosophy, 

1911,  p.  ISO,  and  1912,  p.  206;  "Consciousness  and  Behavior,"  ibid,, 

1912,  p.  15;  "The  Pulse  of  Life,"  ibid.,  1914,  p.  645;  "On  Sensibil- 
ity," ibid.,  1917,  p.  337. 


THE  ELEMENTS  OF  BEHAVIOR         3 

different  from  the  behavior  of  the  stone.  The  light 
rays  reflected  from  the  approaching  vehicle  cause 
him  to  scurry  away  and  those  reflected  from 
food  cause  him  to  approach.  The  impact  of  rain 
may  move  him  toward  the  source  of  impact  rather 
than  away  from  it.  Though,  like  the  stone,  he  is  a 
physical  object,  he  is  not  merely  buffeted  about  by 
his  environment. 

Behavior  Dependent  on  Bodily  Structure 

The  difference  between  the  behavior  of  animals 
and  the  behavior  of  inanimate  objects  depends  upon 
the  fact  that  animals  possess  specialized  structures. 
The  most  important  of  these  structures  are  the  sense 
organs  (receptors),  the  muscles  and  glands  (effec- 
tors), and  the  nervous  system.  The  sense  organs  are 
placed  in  parts  of  the  body  where  they  are  exposed 
to  the  action  of  physical  forces.  The  physical  forces 
that  arouse  the  sense  organs  to  action  are  called 
stimuli.  Because  the  various  kinds  of  sense  organs 
differ  from  each  other  in  structure,  some  are  pro- 
voked to  action  by  one  kind  of  physical  force,  and 
some  by  another. 

The  stimulus  that  commonly  arouses  the  sense 
organ  to  its  characteristic  function  is  called  the  ade- 
quate stimidus.  Light  has  an  effect  upon  the  eye 
that  it  does  not  have  upon  the  ear  or  upon  the  skin. 
Gases  emanating  from  a  flower  act  only  upon  the 
olfactory  sense  organs.     In  addition  to  their  more 


4  GENERAL  PSYCHOLOGY 

frequently  received  stimuli,  many  sense  organs  may 
be  stimulated  by  pressure  or  by  an  electric  current. 

The  physical  forces  that  stimulate  the  sense  or- 
gans differ  in  kind.  Light,  heat,  gravity,  sound, 
and  impact,  are  a  few  of  these  and  each  acts  upon 
some  sense  organ  or  another.  All  stimuli  may  vary 
in  intensity,  and  their  effect  upon  sense  organs  may 
vary  correspondingly. 

Sense  organs  are  connected  with  distant  muscles 
and  glands  by  nerve  structures.  Along  these  nerve 
structures  pass  nervous  impulses  which  result  from 
the  stimulation  of  the  sense  organs  and  which,  on 
reaching  muscles  and  glands,  may  cause  muscular 
contraction  or  glandular  secretion.  It  follows  that 
any  response_to  a  stimulus  can  occur  only  when 
there  is  a  conduction  pathway  established  between 
the  sense  organ  receiving  the  stimulus  and  the 
muscles  concerned  in  the  response.  Such  a  pathway 
is  called  a  neural  arc. 

The  nervous  system  contains  millions  of  nerve 
cells  called  neurones.  These  are  microscopic  in 
cross-section  but  are  occasionally  as  much  as  two 
feet  or  more  in  length.  Each  neurone  consists  of  a 
cell  body  from  which  extend  branching  processes 
which  may  lie  adjacent  to  other  cells.  The  points  of 
contact  so  established  offer  varying  resistance  to  the 
passage  of  nervous  impulses  from  one  cell  to  an- 
other. Such  a  connection  between  two  neurones 
that  permits  the  passage  of  a  nervous  impulse  is 
called  a  synapse.    The  repeated  passage  of  an  im- 


THE  ELEMENTS  OF  BEHAVIOR  5 

pulse  through  a  synapse  is  supposed  to  increase  the 
conductivity  of  the  synapse.  Some  synapses  are 
present  at  birth,  some  occur  in  the  maturation  of  the 
nervous  system,  whereas  others  are  formed  in  the 
course  of  learning. 

The  great  number  of  neurones  and  the  complexity 
of  their  connections  account  for  the  fact  that  an  im- 
pulse leaving  a  particular  sense  organ  may  find  its 
way  to  one  group  of  muscles  at  one  time  and  to 
another  group  of  muscles  at  another  time. 

The  muscles  and  glands  are  the  effectors,  or  or- 
gans of  response.  They  are  so  situated  and  so  con- 
nected with  sense  organs  by  nervous  structures  that 
their  responses  are  coordinated  and  meet  suitably 
most  situations.  Placing  something  in  a  baby's  hand 
causes  the  hand  to  grasp  the  object.  The  nervous 
impulse  that  starts  from  sense  organs  in  the  skin 
finds  its  way  to  the  muscles  which  cause  the  fingers 
to  close.  Without  such  established  pathways  of  con- 
duction, behavior  would  be  inappropriate. 

A  significant  characteristic  of  all  sense  organs  is 
that  they  are  most  sensitive  to  situations  that  affect 
the  life  processes  of  the  animal.  This  adjustment  to 
situations  depends,  first,  upon  the  position  of  the 
sense  organs  in  the  body,  and  second,  upon  the 
structure  of  the  sense  organs  and  upon  the  nature 
of  their  adequate  stimuli.  For  example,  the  eyes  are 
so  placed  in  the  front  of  the  body  as  to  receive  stim- 
uli from  objects  which  the  animal  is  approaching. 
Placed  at  the  rear  they  would  be  less  useful.    The 


6  GENERAL  PSYCHOLOGY 

tongue  has  a  strategic  position,  as  all  food  must  pass 
its  inspection  before  being  swallowed,  and  the  sense 
organs  of  taste  are  affected  as  are  no  other  parts  of 
the  body  by  the  chemical  stimuli  that  are  indicative 
of  the  food  value  of  any  substance  taken  into  the 
mouth. 

Classes  of  Sense  Organs 

According  to  their  location  in  the  body,  sense  or- 
gans are  described  as  the  exteroceptors,  the  intero- 
ceptors,  and  the  proprioceptors.2  Those  on  the  outer 
surface  of  the  body,  which  receive  external  stimuli, 
are  called  exteroceptors.  These  are  the  sense  or- 
gans in  the  skin  that  respond  to  touch,  temperature, 
and  destructive  stimuli,  and  along  with  these  the 
sense  organs  in  the  eyes,  ears,  and  nose.  The  eyes, 
ears,  and  nose  are  also  called  distance  receptors  be- 
cause they  respond  to  stimuli  whose  origin  is  com- 
monly at  a  distance,  a  classification  recognized  by 
as  early  a  writer  as  Aristotle.3 

Besides  the  external  surface  of  the  body  there 
is  the  surface  of  the  enteric  tract,  which  consists  of 
the  mouth,  pharynx,  oesophagus,  stomach,  and  in- 
testines. This  surface  is  also  provided  with  sense 
organs  and  these  are  called  inter oceptors.  Parts  of 
the  external  world  taken  into  the  enteric  tract, 
usually  as  food,  stimulate  the  interoceptors  and  the 
animal's   behavior   is   adjusted  to  what   has   been 

2  Sherrington,  The  Integrative  Action  of  the  Nervous  System, 
lecture  9. 

3  Aristotle,  De  Sensu,  436b. 


THE  ELEMENTS  OF  BEHAVIOR     7 

swallowed.  The  mouse  that  is  outside  a  eat  stimu- 
lates the  cat's  exteroceptors  and  the  cat  responds  in 
a  conspicuous  and  characteristic  way.  Once  the 
mouse  is  transferred  to  the  cat's  enteric  tract,  the 
cat's  reactions  are  less  obvious  but  none  the  less  im- 
portant. Movements  of  rejecting  food,  of  swallow- 
ing, and  of  peristalsis,  the  secretion  of  digestive 
fluids,  and  much  of  the  animal's  observable  be- 
havior result  directly  from  the  stimulation  of  intero- 
ceptors. 

Sense  organs  occur  not  only  on  the  outer  and  the 
inner  surfaces  of  the  animal  but  are  also  found 
deeply  imbedded  in  the  body  tissue.  These  deeply 
imbedded  sense  organs  are  called  proprioceptors. 
Among  the  contractile  muscle  fibers  are  situated  re- 
ceptors that  are  stimulated  by  muscle  tension.  Other 
receptors  in  the  tendons  receive  stimuli  in  a  similar 
way.  The  walls  of  blood  vessels  are  supplied  with 
sense  organs,  so  that  circulatory  changes  affect  the 
animal's  behavior.  In  the  head  are  located  the  semi- 
circular canals  and  the  organs  of  static  sense,  which 
are  stimulated  by  the  movement  or  by  the  position 
of  the  animal.  The  proprioceptors  are  all-important 
in  making  possible  the  coordination  of  bodily  move- 
ments.4 

The  Exteroceptors 
The  most  highly  developed  of  the  exteroceptors 

*  On  the  classes  of  sense  organs  and  their  functions  see  Sherring- 
ton, op.  cit. 


8  GENERAL  PSYCHOLOGY 

are  the  distance  receptors,  namely  the  organs  of 
vision,  hearing,  and  smell.5 

The  Eye. — Anyone  having  an  acquaintance  with 
the  camera  will  find  it  easy  to  understand  the  me- 
chanism of  the  eye.  Light  passes  into  the  eye  | 
through  the  anterior  wall,  which  is  the  transparent 
cornea.  Behind  the  cornea  is  a  diaphragm  called 
the  iris.  Behind  the  iris  is  the  lens  and  behind  the 
lens,  on  the  inner  surface  of  the  eye's  globe-like 
wall,  is  the  sensitive  retina.  The  internal  cavity  of 
the  eye  is  filled  with  a  transparent  mass.  That  in 
front  of  the  lens  is  called  the  aqueous  humor  and 
that  behind  the  lens,  the  vitreous  humor.  As  we 
view  our  own  eye  in  the  mirror  we  see  at  the  center 
a  black  spot,  the  pupil,  surrounded  by  a  pigmented 
ring,  the  iris.  The  pupil  is  a  hole  in  the  iris  and  ap- 
pears black  because  it  is  an  opening  into  the  un- 
lighted  interior  of  the  eye.  It  is  the  color  of  the  iris 
to  which  we  refer  when  we  speak  of  brown  eyes  or 
blue  eyes.  Outside  the  circle  of  the  iris  is  the  white 
sclerotic,  continuous  with  the  cornea,  which,  with 
the  cornea,  constitutes  the  external  wall  of  the  eye. 
(See  Figure  1.) 

By  means  of  six  external  muscles  the  eyeball  is 
moved  about  in  its  socket,  and  in  this  way  a  person 
looks  up  or  down,  to  the  right  or  the  left,  converges 
the  two  eyes  in  fixating  a  near  object  or  so  directs 
them   that   the   axes   of   vision    (the   lines   passing 

c  For  a  more  detailed  account  of  the  structure  and  function  of 
sense  organs  and  nervo\is  system  see  Ladd  and  Woodworth,  Elements 
of  Physiological  Psychology. 


THE  ELEMENTS  OF  BEHAVIOR  9 

through  the  center  of  the  cornea,  pupil,  lens,  and 
fovea)  are  almost  parallel  in  fixating  a  distant  ob- 
ject. To  some  extent  the  eye  may  be  rotated  about 
the  axis  of  vision.     (See  Figure  2.) 

The  iris  is  a  doughnut-shaped  muscle  containing, 
for  the  most  part,  circular  muscle  fibres.     When 


Choroid 


Ciliary- 
muscle 


Figure  1.    schematic  diagram  of  a  section  through  the  eye 


these  fibres  contract,  the  hole  in  the  center,  the  pupil, 
becomes  smaller.  When  the  radiating  fibres  that  it 
contains  contract,  the  pupil  becomes  larger.  For 
near  vision  and  when  stimulated  by  bright  light,  the 
pupil  becomes  smaller.  For  distant  vision  and  in 
dim  light  the  pupil  becomes  larger. 

The  crystalline  lens  is  suspended  all  around  its 
margin  by  the  suspensory  ligament  which  connects 


10 


GENERAL  PSYCHOLOGY 


it  with  a  second  doughnut-shaped  muscle  called  the 
ciliary  muscle.  When  the  circular  fibres  of  this 
muscle  contract,  the  tension  on  the  suspensory  liga- 
ment is  decreased  and,  because  it  is  itself  elastic, 
the  lens  becomes  more  convex.  In  this  shape  it  fo- 
cuses rays  of  light  from  nearby  objects  so  that  the 


/NFER/OR 
OBLIQUE 

FlGUBE  2.      DIAGRAM  OF  THE  POSITION  OB'  THE  EXTERNAL  M0SCLES  THAT 
MOVE   THE  EYEBALL 


images  of  these  objects  are  clearly  defined  on  the 
retina  and  the  images  of  distant  objects  are  blurred. 
When  the  circular  fibres  of  the  ciliary  muscle  are 
relaxed  and  the  radial  fibres  contracted,  the  suspen- 
sory ligament  is  under  greater  tension,  so  that  the 
lens  becomes  less  convex  and  the  images  of  distant 
objects  are  clearly  defined  on  the  retina,  the  images 
of  nearby  objects  being  blurred.  When  the  eyelids 
are  closed  and  the  eye  is  at  rest,  the  circular  fibres 
are  relaxed  and  the  lens  takes  on  this  less  convex 


THE  ELEMENTS  OF  BEHAVIOR         11 

shape,  that  is,  the  eye  is  accommodated  for  distant 
vision. 

Accommodation  for  near  vision,  then,  involves  a 
smaller  hole  in  both  the  iris  and  the  ciliary  muscle 
and  this  is  brought  about  by  the  contraction  of  the 
circular  fibres  in  each.  For  this  reason  accommo- 
dation for  near  vision,  because  of  the  stimulation 
of  sense  organs  in  these  muscles,  gives  us  a  sensa- 
tion of  muscle  strain.  In  distant  vision  and  dim 
light,  where  the  circular  fibres  are  relaxed,  such  sen- 
sations are  practically  absent. 

The  adequate  stimuli  to  the  eye  are  ether  vibra- 
tions whose  frequency  is  more  than  450  million  mil- 
lion vibrations  per  second  and  less  than  790  million 
million.  Lights  of  different  color  have  different  vi- 
bration frequencies  and  intense  lights  have  a  greater 
amplitude  of  vibration  than  have  dim  lights.  White 
sunlight  contains  a  mixture  of  rays  of  all  possible 
vibration  frequencies  to  which  the  eye  is  sensitive. 
Light  emanating  from  a  source  such  as  the  sun  or  a 
candle  either  enters  the  eye  directly  or  impinges 
upon  the  surfaces  of  objects  from  which  it  is  re- 
flected into  the  eye. 

Light  passing  through  the  cornea,  the  aqueous 
humor,  the  lens,  and  the  vitreous  humor  reaches  the 
retina.  In  the  retina  are  found  chemical  substances 
that  change  their  composition  when  acted  upon  by 
light,  and  cell  structures,  some  of  which  are  affected 
by  these  chemical  changes.  Exactly  what  takes  place 
in  the  retina  is  not  known,  but  we  have  reason  to 


12  GENERAL  PSYCHOLOGY 

believe  that  the  pattern  of  the  image  focussed  upon 
the  retina  sets  up  various  changes  in  the  photo- 
chemical substances  and  that  these  changes  affect 
adjacent  cell  structures.  This  is  the  stimulation  that 
gives  rise  to  nervous  impulses. 

Apart  from  supporting  tissue,  the  cell  structure 
of  the  retina  is  made  up  of  nerve-cell  bodies  whose 
long  processes,  or  axones,  constitute  the  optic  nerve; 
of  other  nerve  cells  whose  function  it  is  to  connect 
adjacent  parts  and  layers  of  the  retina;  and  of  the 
rods  and  cones,  which  may  be  regarded  as  the  actual 
sense  organs  for  vision.  (See  Figure  3.)  The  rods 
respond  to  dim  light  as  well  as  to  intense  light, 
whereas  the  cones  respond  only  to  intense  light. 
Colored  light  and  white  light  affect  the  rods  in  the 
same  way,  no  color  vision  resulting  from  such  stim- 
ulation.6 On  the  other  hand  the  cones  give  a  special- 
ized response  to  white  light  and  to  lights  of  different 
colors,  and  it  is  by  means  of  the  cones  that  we  dis- 
tinguish one  color  from  another. 

The  rods  are  lacking  in  the  fovea,  or  that  portion 
of  the  retina  that  is  directly  opposite  the  pupil.  At 
night  when  an  image  of  a  faint  star  falls  upon  the 
fovea,  where  there  are  no  rods,  it  cannot  be  seen, 
but  it  becomes  visible  when  we  glance  to  one  side 
and  so  cause  its  image  to  be  displaced  toward  the 
periphery,  which  is  well  supplied  with  these  sense  or- 
gans for  dim  light.  The  fovea  is  richly  sup- 
plied with  cones  and  is  the  so-called  area  of  distinct 

6  For  the  various  theories  of  color  vision  see  ibid.,  pp.  340ff. 


THE  ELEMENTS  OF  BEHAVIOR 


13 


vision.  The  image  of  the  print  which  is  being  read 
falls  upon  the  fovea,  and  the  print  could  not  be  read 
as  well  if  its  image  were  to  fall  upon  the  peripheral, 
or  outer,  margin  of  the  retina.    The  extreme  periph- 

DirecHon 
\afjight\ 


1BE  Gang lion 


Bipolar 
cells 


Pigment  layer 


To  Brain 


FIGURE   3.      SCHEMATIC  REPRESENTATION   OF  A   SECTION    THROUGH   THE 

BETINA,    SHOWING    THE    POSITION    OF    RODS    AND    CONES,    THE    LAYER    OF 

CONNECTING   NEURONES,   AND   THE   DIRECTION   OF 

FIBRES  OF  THE  OPTIC  NERVE 

ery  contains  only  rods,  and  for  this  reason  any 
object  casting  its  image  there  appears  to  be  without 
color. 

When  the  eye  has  been  exposed  to  intense  light  the 
rods  become  fatigued  and  do  not  function  in  twilight 
until  after  a  period  of  rest.  For  this  reason,  if  we 
enter  a  darkened  theater  in  the  daytime,  we  grope 


14  GENERAL  PSYCHOLOGY 

blindly  for  the  seat,  but  if  we  have  come  in  from 
the  dimly  lighted  street  at  night,  we  find  our  way 
about  without  difficulty.  In  the  dark-room  it  may 
require  a  stimulus  8,000  times  as  great  to  elicit  a  re- 
sponse from  a  light-fatigued  eye  as  is  required  to 
secure  a  response  from  the  thoroughly  rested  eye. 
This  is  true,  of  course,  only  of  parts  of  the  retina 
where  rods  are  found  The  unfatigued  eye  is  some- 
times ambiguously  called  a  "dark-adapted"  eye. 

Ordinarily  both  eyes  are  used  in  vision,  and  are 
so  directed  toward  a  part  of  any  object  that  is  looked 
at  that  the  right  eye  image  and  the  left  eye  image 
fall  on  corresponding  areas  of  the  two  retinae. 
When  this  occurs,  the  two  images  appear  as  one, 
and  are  said  to  fuse.  When  the  two  images  fall 
on  non-corresponding  parts  of  the  two  retinae, 
the  object  is  seen  double.  In  order  that  the  images 
from  a  near  object  may  fall  on  corresponding  parts 
of  the  two  retinae  the  eyes  must  be  so  moved  that 
the  axes  of  vision  converge.  To  secure  fusion 
of  the  images  of  a  distant  object,  the  eyes  must 
be  so  directed  that  their  axes  of  vision  are  almost 
parallel. 

An  important  fact  is  that  vision  enables  animals  to 
respond  to  objects  at  a  distance. 

The  Ear. — Three  parts  of  the  ear  are  distin- 
guished, the  external,  the  middle,  and  the  internal 
ear.  The  external  ear  leads  into  the  middle  ear  and 
is  separated  from  it  by  the  tympanic  membrane. 
When  air  vibrations  impinge  upon  this  membrane,  it 


THE  ELEMENTS  OF  BEHAVIOR         15 

oscillates  back  and  forth  and  causes  movement  in  a 
series  of  three  small  bones  situated  in  the  middle 
ear.  The  movement  of  these  bones  is  transmitted 
in  turn  to  the  fluid  in  the  cochlea,  which  is  a  part  of 
the  inner  ear.  Thus  vibrations  are  set  up  in  this 
fluid  that  have  the  same  rate  as  the  air  vibrations 

Sem  i  circular 
canal 


Ampulla 


Ampulla 


Figure  4.     drawing  from  a  model  op  the  inner  ear,  showing  the 

cochlea,  in  which  are  the  sense  organs  of  hearing;  the  utricle 

and  saccule,  the  organs  of  static  sense;  and 

the  semicircular  canals 


outside.  The  endings  of  a  part  of  the  auditory 
nerve  are  situated  along  the  base  of  a  row  of  rods 
and  hair  cells  that  project  into  the  fluid  contained  in 
the  cochlea.  (See  Figures  4  and  5.)  It  is  not  cer- 
tain whether  the  auditory  nerve  endings  are  stimu- 
lated by  the  vibration  of  this  projecting  row  or  by 
the  vibration  of  the  membrane  at  the  base  of  the 
row. 


16 


GENERAL  PSYCHOLOGY 


The  adequate  stimuli  to  the  ear  are  vibrations  in 
the  surrounding  medium,  usually  in  the  atmosphere. 
These  are  condensation  and  rarefaction  vibrations 
and  their  rate  varies  from  something  more  than  16 
per  second  to  about  50,000  per  second.  Sound  ema- 
nates from  a  vibrating  object,  such  as  a  bell  or  the 


Figure  5.     schematic  section  through  one  of  the  coils  of  the 

cochlea,  showing  the  basilar  membrane  and 

adjacent  structures 

vocal  cords-  of  an  animal,  and  the  vibrations  are 
taken  up  by  the  atmosphere  and  conveyed  to  the 
tympanic  membrane.  This  enables  an  animal  to  re- 
spond to  objects  at  a  distance. 


THE  ELEMENTS  OF  BEHAVIOR 


17 


The  Nose. — In  the  wall  of  a  recess  that  opens  upon 
the  air  passages  of  the  nose  are  found  the  sense  or- 
gans for  odor.  The  actual  sense  organs  for  odor  are 
long  nerve  cells  embedded  between  epithelial  cells 
and  with  long  processes  extending  to  the  surface  of 
the  mucous  membrane.  In  the  other  direction  nerve 
fibres  extend  from  these  cells  to  the  brain.  (See 
Figure  6.) 


Olfactory 
cell— 


Epithelial 
-cell 


FlGUBE    6. 


SECTION    THROUGH    THE    OLFACTORY    MEMBRANE    SHOWING 
OLFACTORY   CELLS  AND   SUPPORTING   CELLS 


The  adequate  stimuli  to  the  olfactory  sense  organs 
are  gases  in  the  atmosphere.  These  emanate  from 
volatile  substances,  and  upon  reaching  the  nose  are 
inhaled  past  the  olfactory  area.  This  makes  it  pos- 
sible for  the  animal  to  respond  to  objects  at  a  dis- 
tance, although  the  stimulus  may  be  slow  in  reach- 
ing the  animal  and  gives  but  little  indication  of  the 
direction  of  its  source. 

Organs  of  Touch. — There  are  two  kinds  of  sense 
organs  for  touch.  On  parts  of  the  body  where  hair 
is  absent,  such  as  the  lips  and  the  palm  of  the  hand, 


18 


GENERAL  PSYCHOLOGY 


are  found  touch  corpuscles  that  enclose  a  core  of 
cells  and  nerve  fibres.  On  the  hairy  surfaces  the 
nerve  fibres  are  found  coiled  about  the  roots  of  the 
hairs.  The  touch  corpuscles  (shown  in  Figure  7) 
are  plentiful  in  some  areas  of  the  skin  such  as  lips, 
tongue,  and  finger  tips,  and  sparsely  distributed  in 
other  areas. 

The  adequate   stimulus  for  touch  is  deforming 


Branching 

'of 
Sensory 
neurone 


FlGUEE  7.      TOUCH   CORPUSCLE  FROM  THE  PALM  OF  THE  HUMAN  FINGEB 
(AFTER  BANVIEB) 

pressure  upon  the  skin  adjacent  to  a  corpuscle,  or 
to  the  "  windward"  of  a  hair,  or  pressure  upon  the 
hair  itself,  which  stimulates  the  nerve  ending  at  its 
roots. 

Warmth  Or  gams. — The  warmth  sense  organs  are 
probably  distinct  from  the  cold  sense  organs.  This 
conclusion  is  suggested  by  the  fact  that  spots  on  the 
skin  sensitive  to  warmth  are  much  fewer  than  spots 
sensitive  to  cold.  There  are,  on  the  average,  two 
or  three  such  warmth  spots  to  the  square  centimeter 
of  skin  surface.  The  organ  is  probably  a  cylindrical 
end  bulb  found  rather  deeply  imbedded  in  the  skin. 


THE  ELEMENTS  OF  BEHAVIOR         19 

The  adequate  stimulus  for  warmth  is  anything 
that  increases  within  certain  limits  the  temperature 
of  the  sense  organ.  This  may  be  done  by  the  con- 
tact of  the  skin  with  objects  whose  temperature  is 
higher  than  that  of  the  sense  organ  at  the  time,  by 
radiant  heat  emanating  from  objects  at  a  distance, 
and  by  the  dilatation  of  neighboring  blood  vessels. 
Dilatation  may  be  produced  by  the  application  to 
the  skin  of  such  substances  as  mustard  or  pepper. 

Cold  Organs. — The  sense  organs  for  cold  prob- 
ably have  the  form  of  end  bulbs,  lying  nearer  the 
surface  of  the  skin  than  do  the  warmth  organs.  The 
spots  sensitive  to  cold  average  between  10  and  15 
per  square  centimeter  of  skin  surface. 

The  adequate  stimulus  for  cold  is  anything  that 
reduces  within  certain  limits  the  temperature  of  the 
sense  organ.  This  may  be  done  by  the  contact  of  the 
skin  with  objects  whose  temperature  is  lower  than 
that  of  the  sense  organ  at  the  time,  by  skin  evapora- 
tion, by  heat  radiation  from  the  skin,  and  by  the  con- 
striction of  neighboring  blood  vessels.  Certain  sub- 
stances, such  as  menthol,  stimulate  the  cold  organ 
either  by  direct  action  or  possibly  by  causing  blood- 
vessel constriction.  A  cold  spot,  curiously,  may  be 
stimulated  by  a  pointed  hot  rod  of  a  temperature 
45  to  50  degrees  C.  (The  temperature  of  the  blood 
is  37  degrees  C).  When  such  a  result  is  obtained, 
we  have  what  is  called  paradoxical  cold. 

Pam  Organs. — Certain  free  nerve  endings  that 
are  found  distributed  over  most  of  the  body  surface 


20  GENERAL  PSYCHOLOGY 

are  probably  sense  organs  for  pain.  Pain  is  also 
elicited  by  the  stimulation  of  parts  of  the  body  other 
than  the  skin  surface,  and  possibly  results  from  the 
intense  stimulation  of  sense  organs  not  primarily 
concerned  with  pain. 

The  adequate  stimuli  to  the  pain  organs  are  me- 
chanical, thermal,  and  chemical,  and  must  be  of 
much  greater  intensity  than  those  that  are  neces- 
sary to  arouse  the  organs  of  touch  and  temperature. 
The  prolongation  of  these  intense  stimuli  is  usually 
injurious  to  the  animal. 

The  Interoceptors 

Taste  Organs. — The  receptors  for  taste  are  situ- 
ated on  the  upper  surface  and  the  margin  of  the 
tongue,  a  few  occurring  on  the  uvula,  the  epiglottis, 
and  the  larynx.  They  are  in  the  form  of  end  bulbs 
penetrated  by  the  sensory  nerve  ending  and  having 
a  minute  opening  on  the  external  surface.  They  are 
grouped  together  in  certain  of  the  papillae  of  the 
tongue,  which  are  easily  observed  as  small  emi- 
nences. 

The  adequate  stimuli  for  taste  may  be  divided 
into  four  classes  according  to  the  responses  they 
elicit:  sweet,  sour,  salt,  and  bitter  substances,  and 
there  are  probably  four  corresponding  kinds  of  taste 
organs.  In  order  to  stimulate  the  organs,  the  sub- 
stance must  be  soluble.  Many  substances  such  as 
peppermint,  onion,  cantaloupe,  or  cheese  are  popu- 
larly regarded  as  having  characteristic  tastes,  but 


THE  ELEMENTS  OF  BEHAVIOR         21 

these  are  for  the  most  part  odors.  When  the  nose 
is  carefully  packed,  so  that  no  respired  air  reaches 
the  olfactory  surface,  it  is  impossible  to  distinguish 
clam  bouillon  from  beef  bouillon,  black  coffee  from 
quinine  solution,  honey  from  molasses,  or  lemon 
juice  from  vinegar.  These  substances  are  then  re- 
sponded to  as  though  they  were  merely  salt,  bitter, 
sweet,  or  sour. 

Other  Interoceptors. — Sense  organs  are  found 
throughout  the  mucous  membrane  of  the  alimentary 
tract.  Because  of  their  isolated  position,  less  is 
known  concerning  their  action  than  is  known  of  the 
function  of  sense  organs  more  accessible  to  experi- 
mentation. They  are  more  sparsely  distributed 
than  are  the  sense  organs  on  the  skin  and,  though 
some  respond  to  pressure  and  to  temperature,  they 
are  most  affected  by  chemical  stimuli. 

Their  adequate  stimuli  are  food  substances,  inter- 
nal secretions,  and  the  movements  of  the  enteric 
tract.  Thirst  results  from  dryness  of  the  pharynx, 
and  hunger  from  a  vigorous  peristaltic  movement 
ofthe  empty  stomach  that  may  occur  at  intervals  of 
about  one  minute. 

The  Proprioceptors 

Semicircular  Canals. — These  organs,  though  not 
auditory  in  function,  are  contained  in  three  com- 
municating cavities  constituting  a  part  of  the  inner 
ear.  (See  Figure  4.)  The  cavities  are,  roughly 
speaking,  ringlike  in  form,  each  one  being  set  at 


22  GENERAL  PSYCHOLOGY 

right  angles  to  the  other  two.  Cells  with  hairlike 
processes  project  into  the  fluid  which  the  cavities 
contain.  When  the  head  is  rotated  in  any  plane,  the 
contained  fluid,  in  at  least  one  of  these  canals,  due  to 
inertia,  lags  behind  the  walls  of  the  cavity.  Because 
of  this,  the  projecting  hair  processes  are  bent  to  one 
side  and  the  adjacent  nerve  fibres  are  stimulated. 
This  action  may  be  understood  by  thinking  of  a 
bucket  filled  with  water  into  which  projects  moss 
that  is  attached  to  the  wooden  surface.  When  the 
bucket  is  rotated,  the  water  lags  behind  and  the 
moss  is  bent.  If  the  bucket  is  kept  twirling  for  a 
short  time,  the  water  takes  up  its  motion  and  con- 
tinues to  move  when  the  bucket  is  stopped,  thus 
reversing  the  direction  of  the  moss.  The  semicircu- 
lar canals  act  in  a  similar  way,  so  that  when  a  person 
has  been  whirled  for  a  time  in  a  revolving  chair  and 
suddenly  stopped,  he  responds  as  though  he  were 
being  turned  in  the  opposite  direction. 

The  adequate  stimulus  to  these  sense  organs  is 
rotary  movement  of  the  head. 

Static  Organs. — On  each  side  of  the  head  adja- 
cent to  the  semicircular  canals  and  contained  in  bony 
cavities  are  two  small  membranous  sacs,  the  utricle 
and  saccule.  (See  Figure  4.)  Within  them  is  a  gel- 
atinous mass  into  which  project  sensory  hair  cells. 
Among  the  hairs  are  found  small  particles  of  cal- 
cium carbonate,  called  otoliths.  The  pressure  of  the 
otolith-weighted  mass  upon  the  hair  cells  varies  with 
the  position  and  movement  of  the  head. 


THE  ELEMENTS  OF  BEHAVIOR         23 

The  adequate  stimulus  to  these  organs  is  the  posi- 
tion of  the  head  with  reference  to  gravity,  or  motion 
of  the  head  in  any  direction. 

Muscle  and  Tendon  Sense  Organs  (Kinesthetic 
Organs). — In  the  muscles  are  found  sensory  ''spin- 
dles" made  up  of  modified  muscle  fibres  and  free 
nerve  endings.  Similar  organs  are  found  in  the 
walls  of  blood  vessels  and  in  the  tendons. 

The  adequate  stimulus  for  these  organs  is  the  me- 
chanical pressure  and  state  of  strain  in  muscles  and 
tendons  that  results  from  any  bodily  movement. 

The  Nervous  System 

A  stimulus  starts  a  chain  of  neural  events  and  a 
response  terminates  it.  Between  stimulus  and  re- 
sponse many  things  occur  in  the  nervous  system. 

The  principle  has  already  been  stated  that  a  re- 
sponse can  not  result  from  a  stimulus  unless  there  is 
a  pathway  of  nervous  conduction  between  receptor 
and  effector.  The  whole  nervous  system  is  an  intri- 
cate arrangement  of  such  pathways. 

The  brain  is  contained  in  the  skull,  and  the  spinal 
cord  is  contained  in  the  vertebral  column.  The  brain 
and  spinal  cord  constitute  the  central  nervous  sys- 
tem. Sensory  nerves  lead  from  the  sense  organs  to 
the  spinal  cord  and  brain.  Motor  nerves  leave  the 
brain  and  the  spinal  cord  and  lead  to  skeletal  mus- 
cles. These  sensory  and  motor  nerves  constitute 
the  peripheral  nervous  system.    In  addition  to  the 


24 


GENERAL  PSYCHOLOGY 


central  and  peripheral  nervous  systems  there  is  the 
autonomic  nervous  system.  This  system  serves  the 
involuntary  muscles  and  the  glands.  The  muscles 
that  it  affects  are  distinct  in  kind  from  the  skeletal 
or  voluntary  muscles,  being  "unstriped"  in  appear- 
ance and  slow  in  their  action.     Through  the  auto- 


Sfljnal  cor<} 


'Gland 


muscle 


or  striped 
muscle 


AUTONOMIC 


PERIPHERAL 


Figure  8.     the  belation  of  efferent  fibres  of  the  autonomic 

and  the  peripheral  nervous  systems  to  the  central 

nervous  system 

nomic  system  the  central  nervous  system  is  con- 
nected with  such  effectors  as  sweat  glands,  salivary 
glands,  tear  glands,  adrenal  glands,  liver,  spleen, 
stomach,  intestine,  rectum,  bladder,  genitals,  heart, 
and  blood  vessels.  The  autonomic  has  much  the 
same  function  as  the  peripheral  nervous  system. 
The  relation  of  the  three  systems  may  be  seen  from 
Figure  8. 


THE  ELEMENTS  OF  BEHAVIOR         25 

The  Spinal  Cord. — A  cross  section  of  the  spinal 
cord  shows  an  outer  white  area  and  an  inner  gray- 
area  whose  shape  varies  at  different  levels  of  the 
cord  but  preserves  a  general  resemblance  to  the  let- 
ter H.  (See  Figure  9.)  The  outer  white  area  is 
composed  of  longitudinal  columns  of  nerve  fibres  en- 


Dorsa2  root 


Posterior 
horn 


Anterior 
horn 


Central 
root 

Figure  9.  schematic  section  of  the  spinal  cord,  the  dotted 
area  in  the  center  is  gray,  due  to  the  presence  of  nerve  cell 
bodies  and  unmedullated  fibres.  the  outer  area  is  made  up  of 
columns  of  longitudinal  fibres.  areas  of  motor  fibres  are  marked 
m.,  and  areas  of  sensory  fibres  are  marked  s.  other 
areas  are  mainly  connecting  fibres 


cased  in  their  white  medullary  sheaths.  The  inner 
gray  area  is  made  up  of  two  posterior  (or  dorsal) 
and  two  anterior  (or  ventral)  horns  with  an  isthmus 
of  connecting  or  commisural  fibres.  Its  gray  ap- 
pearance is  due  to  the  presence  of  nerve  cell  bodies 
lacking  the  white  medullary  sheath  that  gives  their 
color  to  the  outer  columns. 

The  Brain. — The  cerebral  hemispheres  constitute 


26 


GENERAL  PSYCHOLOGY 


the  largest  part  of  the  human  brain.  A  cross  section 
of  one  of  these  hemispheres  shows  an  outer  layer  of 
gray  matter  that  is  called  the  cerebral  cortex.     This 

r<°r?m'T7G?  branches 
of  spina?  cord 


Figure  10.    schematic  uepbesentation  of  sensory  neubone 

is  made  up  of  un-medullated  cell  bodies  and  nerve 
fibres.  A  large  part  of  the  interior  of  the  brain  is 
seen  to  be  composed  of  white  medullated  tracts,  al- 
though there  are  distributed  in  this  area  numerous 
patches  of  gray  matter. 


THE  ELEMENTS  OF  BEHAVIOR         27 

Neural  Arcs. — A  sensory   (or  afferent)  neurone 

starts  at  a  sense  organ  and  terminates  in  the  spinal 

cord.     Its  branched  processes,  extending  upward 

Dendrites 


Striated 

muscle 

fibers 

\ 


FIGURE  11.     SCHEMATIC  REPRESENTATION  OF  MOTOR  NEURONE 


and  downward,  form  a  part  of  the  sensory  columns 
of  the  cord,  and  from  these  columns  its  processes 
enter  the  dorsal  horn  at  various  levels.  Connecting 
neurones,  sometimes  called  association  or  internun- 
cial  neurones,  carry  impulses  from  the  sensory  sys- 


28  GENEEAL  PSYCHOLOGY 

terns  to  motor  systems.  Every  neural  arc  contains 
at  least  one  such  connecting  neurone  interposed  be- 
tween its  sensory  neurone  and  its  motor  neurone. 
The  cortex  has  many  more  of  these  connecting  neu- 
rones than  has  the  spinal  cord,  so  that  in  the  brain 
there  are  many  intricate  pathways,  any  one  of  which 
an  impulse  may  follow,  depending  upon  the  varying 
resistance  in  the  synapses  encountered.  Figure  12 
shows  the  relation  of  these  connecting  neurones  to 
sensory  and  motor  systems. 

The  motor  pathways  in  the  central  nervous  sys- 
tem consist  chiefly  of  pyramidal  tracts  running  from 
the  cortex  to  the  anterior  horn  of  the  cord.  From  the 
anterior  horn  motor  (or  efferent)  neurones  lead  to 
the  muscles. 

When  an  impulse  passes  from  a  sense  organ  to  a 
muscle  by  way  of  a  sensory  neurone,  connecting  neu- 
rones in  the  spinal  cord  and  a  motor  neurone,  its 
pathway  is  called  a  reflex  arc*  (See  Figure  12.) 
Such  reflex  arcs  are  usually  instinctive  mechanisms. 
A  frog  with  its  brain  removed  responds  to  many 
stimuli  by  means  of  these  reflex  arcs. 

Regulatory  Character  of  Responses 

A  significant  characteristic  of  responses  is  that  in 
general  they  meet  successfully  the  situations  that 
contribute  the  stimuli  that  call  them  forth.  For  ex- 
ample, a  foreign  object  in  the  nose  calls  forth  a 
sneeze  response  that  removes  the  irritating  object. 


THE  ELEMENTS  OF  BEHAVIOR 


29 


Musde 


Spinal  cord 


SfaH 


FlGURE   12.      SCHEME  OF  NEURAL  PATHWAYS   FROM   A   SENSE   ORGAN  IN 

THE  SKIN   TO  A  MUSCLE.      ARROWS   INDICATE  POSSIBLE   COURSES   TAKEN 

BY   A    NERVOUS    IMPULSE.      THE    NEURONES   ARE   SHOWN   ENLARGED  OUT 

OF  ALL  PROPORTION  TO  THE  SIZE  OF  THE  BRAIN 

AND  CORD    (AFTER  STARR) 


30  GENERAL  PSYCHOLOGY 

The  visual  stimulus  of  a  fleeing  mouse  causes  the  cat 
to  make  movements  that  result  in  the  mouse's  cap- 
ture, just  as  the  mouse,  receiving  the  visual  stimu- 
lus of  a  cat,  is  impelled  to  make  movements  of  flight. 
A  baby  will  grasp  the  person  who  holds  him  if  the 
support  is  suddenly  released.  One  of  the  responses 
to*  stumbling  is  extending  the  hands,  and  this  pro- 
tects the  more  vital  parts  of  the  body  from  injury.7 

A  baby  cries  when  he  is  hungry,  cold,  frightened, 
or  in  pain.  This  serves  to  bring  his  nurse  to  the 
spot.  We  might  contrast  this  mutual  regulation  in 
human  beings  with  the  behavior  of  such  a  simple 
animal  as  the  frog.  Frogs  never  come  to  each  other's 
rescue,  even  though  they  have  pain  and  danger  calls. 
The  only  call  which  summons  the  frog's  fellow  is  the 
mating  call. 

A  familiar  response  of  the  dog  is  his  scratching 
reflex.  If  stimulated  with  a  pin  point  behind  the 
right  shoulder,  the  dog  makes  rapid  oscillatory 
movements  with  the  right  hind  leg,  the  utility  of 
which  movement  is  obvious.  If  the  same  stimula- 
tion be  applied  a  short  distance  above  the  tail  at  a 
spot  which  the  scratching  foot  cannot  reach,  the 
tongue  makes  reflex  licking  movements  even  though 
the  dog  does  not  attack  the  spot  with  his  mouth. 
Thus  stimulation  of  any  part  of  the  body  brings  into 
play  regulatory  responses  that  usually  meet  the  sit- 
uation appropriately. 

The  stimuli  accepted  by  the  distance  receptors 

'  Smith,  "Regulation  in  Behavior,"  Journal  of  Philosophy,  1914. 


THE  ELEMENTS  OF  BEHAVIOR         31 

result  in  responses  that  adjust  the  animal  to  the 
good  or  evil  that  is  about  to  befall  it.  In  their 
simplest  form  these  responses  turn  the  animal 
toward  or  away  from  the  stimulus,  or  increase  or  de- 
crease the  distance  separating  object  and  animal. 

Delayed  Utility  of  Responses 

The  utility  of  a  response  is  often  not  evident  until . 
a  long  time  after  it  is  given.  The  lapse  of  time  oc-. 
curring  between  the  response  and  the  advantage  the 
animal  reaps  from  it  often  makes  the  response  seem 
a  matter  of  prudent  deliberation  on  the  part  of  the 
animal,  when  this  is  really  not  the  case.  All  re- 
sponses of  lower  animals  are  evoked  by  present  sit- 
uations, even  when  the  future  situations  to  which 
they  adjust  the  animal  are  far  distant.  This  ad- 
justment to  the  future,  in  particular  cases,  may  be 
fruitless,  as  the  probable  event  may  never  transpire, 
but  the  response  occurs  regardless  of  this  uncer- 
tainty. These  probable  events  are  the  situations  in 
the  environment  of  the  species  that  recur  periodi- 
cally, such  as  night,  or  high  tide,  or  winter,  or  new 
laid  eggs.  The  brooding  hen  does  not  foresee  the 
consequences  of  her  act,  but  is  merely  responding 
to  the  eggs,  the  nest,  and  the  physiological  changes 
in  her  own  body.  The  situation  that  causes  the 
squirrel  to  store  food  in  October  is  not  the  inevitable 
scarcity  of  nuts  during  the  following  winter,  but 
rather  the  surplus  food  supply  in  the  autumn.  Some 


32  GENERAL  PSYCHOLOGY 

anticipatory  reactions  of  animals  are  of  use  only  to 
others,  and  an  animal  often  dies  before  the  utility 
of  his  act  is  manifest.  A  conspicuous  example  of 
this  is  the  behavior  of  the  solitary  wasp  in  catching 
and  storing  food  for  an  offspring  whose  birth  she 
does  not  ordinarily  survive. 

The  biological  utility  of  the  mating  and  nest  build- 
ing of  birds  is  the  birth  and  shelter  of  the  offspring. 
The  bird,  however,  responds  to  the  situation  at  the 
time  with  as  little  regard  for  the  future  as  man  has 
when  he  coughs  or  sneezes  in  response  to  foreign 
objects  in  the  throat  and  nose. 

Appakent  Absence  of  Utility  of  Some  Responses 

Although  we  may  usually  expect  to  find  some  use 
served  by  every  response,  there  are  many  cases  of 
inappropriate  reactions.  For  example,  the  instinct 
tha»t  leads  a  dog  to  run  barking  beside  the  front 
wheels  of  an  automobile  seems  to  serve  no  useful 
purpose  either  to  dog  or  driver.  If  we  remember, 
however,  that  the  dog  is  the  descendant  of  the  wolf 
and  that  the  wolf  in  killing  his  prey  must  depend 
upon  the  pack  for  assistance,  it  is  clear  that  there 
was  a  time  when  this  reaction  was  of  service.  By 
these  movements  that  are  so  annoying  to  us  in  the 
dog,  the  single  wolf,  fleeter  than  his  fellows,  over- 
takes and  turns  back  his  prey  so  that  the  whole  pack 
take  part  in  the  killing.  The  absence  of  utility  in 
the  dog's  act  is  due  only  to  the  fact  that  he  lives  in 


THE  ELEMENTS  OF  BEHAVIOR         33 

artificial  conditions.  Many  of  man's  inappropriate 
responses  that  are  spoken  of  as  immoral  have,  at 
some  period  in  the  history  of  the  race,  been  a  neces- 
sary means  to  his  survival. 

Living  in  a  complex  civilization  makes  many  of 
our  original  reaction  tendencies  inappropriate.  Our 
proneness  to  anger  toward  telephone  operators,  or 
toward  the  automobile  that  resists  our  efforts  to 
start  it,  is  often  of  no  use  to  us.  Our  natural  equip- 
ment does  not  include  appropriate  responses  to  these 
situations.  Loudness  of  voice  and  violent  action 
are  the  innate  responses  to  situations  not  wholly  dis- 
similar to  an  irritating  operator  or  to  a  recalcitrant 
machine,  so  these  are  the  responses  given  by  the  un- 
regenerate.  When  a  man  steps  in  front  of  us  in  the 
line  waiting  for  theater  tickets,  our  adrenal  re- 
sponse, promoting  as  it  does  the  clotting  of  the 
blood,  prepares  us  for  actual  bloodshed,  although 
this  is  usually  needless  as  we  may  never  come  to 
blows. 

Orientation,  Locomotion,  and  Intervention 

A  response  to  stimulation  is  often  a  turning 
toward  or  away  from  certain  objects.  These  objects 
are  usually  themselves  the  source  of  the  stimulus 
that  causes  the  turning.  The  altered  position  gen- 
erally serves  one  of  two  purposes.  It  may  put  the 
animal  in  a  position  to  employ  mouth  or  legs  to  ad- 
vantage, as  when  a  startled  animal  takes  up  an  atti- 


34  GENERAL  PSYCHOLOGY 

tude  of  defense  or  prepares  for  flight.  It  may 
change  the  direction  of  the  animal's  sense  organs 
with  reference  to  the  provoking  stimulus  or  with 
reference  to  other  stimuli  usually  associated  with 
this.  For  example,  the  horse  cocks  his  ear  toward 
the  unusual  sound,  thus  bringing  the  sense  organ 
further  into  play.  The  herd  wheel  in  the  direction 
from  which  danger  may  be  expected  in  response  to 
the  danger  cry  of  the  leader.  Taking  up  a  posture 
that  permits  the  appropriate  action  of  receptors  or 
effectors,  or  that  withdraws  receptors  from  stimu- 
lation, is  called  orientation. 

Many  of  an  animal's  movements,  such  as  walking, 
running,  jumping,  swimming,  crawling,  or  flying, 
serve  to  impel  him  from  place  to  place.  Movements 
that  cause  a  change  of  location  of  the  animal  as  a 
whole  are  called  locomotion. 

Responses  of  orientation  and  locomotion  fre- 
quently occur  simultaneously.  If  a  cow  is  standing 
by  the  roadside  facing  us  as  we  approach  in  a  vehi- 
cle, she  merely  maintains  her  orientation  with  re- 
spect to  the  vehicle,  by  slowly  turning  her  head  as 
we  pass.  If,  on  the  other  hand,  we  approach  her  on 
the  flank,  her  head  turns  toward  the  road  in  response 
to  the  sound,  but  she  is  also  actuated  to  flight.  In 
order  to  keep  her  eye  on  the  vehicle  and  at  the  same 
time  to  move  forward,  she  wheels  slowly  and  crosses 
the  road  ahead  of  us.  What  seems  to  be  a  mere  per- 
versity in  the  cow  is  explained  as  a  combination  of 
these  two  action  systems. 


THE  ELEMENTS  OF  BEHAVIOR         35 

Orientation  and  locomotion  change  the  position 
of  the  animal  with  reference  to  objects  in  the  en- 
vironment, but  do  not  change  the  position  of  sur- 
rounding objects  with  reference  to  each  other.  Re- 
sponses that  serve  to  redistribute  the  parts  of  the 
outside  world  will  be  called  intervention.  Respon- 
ses of  intervention,  as,  for  example,  picking  up  an 
object,  always  involve  orientation,  and  often  loco- 
motion as  well. 

Movements  of  orientation,  locomotion,  and  inter- 
vention all  serve  to  bring  new  stimuli  to  bear  on 
the  animal  and  these  in  turn  are  succeeded  by  new 
responses.  The  proportion  of  intervention  respon- 
ses in  higher  animals  is  strikingly  greater  than  in 
lower  forms.  In  response  to  variations  of  season 
and  food  supply,  birds  employ  orientation  and  loco- 
motion, thereby  bettering  their  environment.  The 
hermit  crab  travels  about  until  he  finds  a  shell  that 
affords  him  shelter.  Man,  on  the  other  hand,  by 
means  of  his  elaborate  intervention  responses,  so 
constructs  the  world  about  him  as  to  lessen  his  de- 
pendence upon  movements  of  orientation  and  loco- 
motion, with  a  resulting  increase  of  convenience  and 
safety.  He  plants  his  crops  and  breeds  his  cattle 
instead  of  searching  for  wild  vegetables  or  game. 
He  is  born  naked  and  assumes  or  discards  clothing 
according  to  the  weather.  He  brings  together  into 
one  place  shelter,  clothing,  bed,  food,  water,  fuel, 
utensils,  mate,  and  offspring.  From  his  immediate 
neighborhood  he  removes  dirt,  enemies,  and  danger- 


36  GENERAL  PSYCHOLOGY 

ous  objects.  He  constructs  tools  and  weapons  that 
are  of  assistance  to  him  in  further  movements  of  in- 
tervention. By  an  elaboration  of  mechanical  con- 
trivances he  devises  vehicles  that  take  the  place  of 
his  legs  in  locomotion,  and  instruments  that  extend 
the  range  and  accuracy  of  his  sense  organs. 

Internal  Responses 

The  three  types  of  responses  just  mentioned,  ori- 
entation, locomotion,  and  intervention  consist  in 
movements  of  the  skeletal  muscles.  Animals  re- 
spond also  by  movements  of  visceral  muscles  and  by 
glandular  secretion.8  The  dog  that  smells  appetiz- 
ing food  not  only  turns  toward  the  food,  approaches 
and  tears  it  with  his  teeth,  but  also  responds  by  cer- 
tain internal  reactions  of  peristalsis  and  secretion. 
Peristalsis  is  a  wave-like  muscular  constriction  of 
the  enteric  tract  that  serves  to  carry  food,  once 
taken  into  the  mouth,  into  stomach  and  intestines, 
and  to  knead  the  food  in  such  a  way  that  all  parts  of 
it  are  brought  into  contact  with  the  secreting  and 
absorbing  walls.  Secretions  into  the  enteric  tract 
serve  to  prepare  the  food  for  absorption.  The  prin- 
cipal glands  that  serve  digestion  are  in  the  mouth, 
stomach,  intestines,  pancreas,  and  liver.  At  the 
sight  or  smell  of  food,  the  mouth  and  stomach  are 
prepared  by  their  secretions  to  receive  it.  The  flow 
of  these  secretions  is  later  increased  by  the  presence 

s  For  a  detailed  account  of  such  internal  responses  see  Cannon, 
Bodily  Changes  in  Pain,  Hunger,  Fear,  and  Rage. 


THE  ELEMENTS  OF  BEHAVIOR         37 

of  food  in  the  mouth,  by  the  movements  of  chewing, 
and  by  the  peristalsis  of  which  swallowing  is  a  part. 

When  a  cat  is  enraged  by  a  barking  dog,  it  not  only 
'  'spits"  and  assumes  the  posture  of  defense,  but  its 
peristalsis  ceases,  and  the  blood  vessels  so  change 
their  size,  by  the  play  of  minute  muscles  in  the  ves- 
sel walls,  that  a  greater  blood  stream  reaches  the 
fighting  and  fleeing  groups  of  skeletal  muscles. 
Sugar  stored  in  the  liver  is  liberated.  Prom  the 
adrenal  glands  adrenin  is  secreted  and  poured  into 
the  blood,  with  the  result  that  fatigue  is  counteracted 
and  the  vasomotor  condition  and  absence  of  peris- 
talsis are  maintained.  Heart  beat  and  respiration 
show  an  appropriate  increase  of  amplitude  and  rate. 
As  a  rule,  internal  responses  do  not  occur  alone,  but 
accompany  movements  of  orientation,  locomotion, 
and  intervention.  They  facilitate  these  movements 
and,  in  turn,  are  further  excited  by  them. 

Emotional  expression  is  made  up  of  overt  bodily 
movements  and  of  characteristic  internal  responses 
accompanying  them.  The  grouping  of  responses  in 
each  emotion  shows  great  resistance  to  the  rear- 
ranging effects  of  training,  as  is  indicated  by  their 
fundamental  similarity  in  diverse  races.  Grief, 
merriment,  anger,  and  love  are  expressed  in  much 
the  same  way  the  world  over.  They  are  aroused, 
however,  by  varying  situations  in  different  socie- 
ties.9 


9  See  Darwin.  The  Expression  of  the  Emotions  in  Man  and  in  Ani- 
mals, pp.  83-115. 


38  GENERAL  PSYCHOLOGY 

When  a  person  is  stirred  to  action  by  the  internal 
responses  of  rage,  fear,  or  love,  we  say  he  is 
"moved."  This  is  more  than  a  mere  figure  of 
speech.  A  situation  that  hampers  movement  causes 
the  response  of  struggling  with  head,  body,  arms, 
and  legs,  but  it  also,  either  directly  or  because  of  the 
struggling,  causes  certain  internal  responses  like 
those  described  in  the  case  of  the  enraged  cat.  These 
internal  responses  stimulate  proprioceptors  in  the 
viscera.  The  impulses  so  aroused  are  conveyed 
along  neural  arcs  to  the  muscles  engaged  in  strug- 
gling, and  the  action  of  these  muscles  is  thereby 
strengthened  and  sustained.  If  the  pathways  of  ner- 
vous conduction  between  proprioceptors  and  skele- 
tal muscles  should  be  severed,  this  reenforcement 
would  not  take  place  and  the  struggling  movements 
would  be  less  energetic  and  shorter-lived. 

The  secretion  into  the  blood  of  adrenin  from  the 
adrenal  glands  reduces  the  peristaltic  movements 
in  the  intestinal  tract,  increases  by  its  action  upon 
blood  vessels  the  amount  of  blood  in  the  skeletal 
muscles,  and,  by  direct  contact,  makes  more  ener- 
getic the  contraction  of  the  skeletal  muscles  involved 
in  the  expression  of  rage.  It  probably  promotes 
clotting  of  the  blood,  which  is  of  advantage  in  case 
the  ensuing  fight  results  in  the  animal's  being 
wounded. 

This  action  of  adrenin  is  another  way  of  eliciting  a 
response.  Between  the  gland  and  the  muscles  acted 
upon  there  is  no  nervous  connection.     The  blood 


THE  ELEMENTS  OF  BEHAVIOR         39 

stream  carries  the  gland's  secretion  to  the  muscles, 
and  the  secretion  has  a  direct  chemical  action  upon 
the  muscle  tissue.  Thus  the  direct  action  of  internal 
secretions  from  ductless  glands  is  complementary 
to  the  conduction  of  impulses  from  visceral  pro- 
prioceptors through  neural  arcs.  The  effect  of  these 
secretions  is  less  prompt  than  is  the  effect  of  neural 
reenforcement,  but  persists  for  a  longer  time. 

The  Action  of  a  Stimulus-Response  Mechanism 

Many  weak  stimuli,  which  act  upon  sense  organs 
without  causing  a  response,  will  be  found  to  call 
forth  a  response  when  the  stimuli  are  increased  in 
intensity.  A  stimulus  of  an  intensity  just  sufficient 
to  bring  about  a  reaction  is  called  a  threshold  stimu- 
lus or  liminal  stimulus.  This  is  not  to  be  confused 
with  the  term  "adequate  stimulus,"  which  denotes 
the  kind  or  class  of  stimuli  ordinarily  capable  of 
exciting  a  sense  organ.  We  may  give  a  baby  a  qui- 
nine solution  so  weak  that  he  will  swallow  it  as 
though  it  were  pure  water.  If  the  strength  of  the 
solution  is  gradually  increased,  we  reach  a  point  at 
which  the  baby  will  grimace  and  turn  his  head  away. 
This  constitutes  the  threshold  point. 

If,  instead  of  increasing  in  intensity  a  stimulus 
that  is  less  intense  than  the  threshold  stimulus,  we 
repeat  such  a  stimulus  again  and  again,  a  response 
may  be  elicited.  Bringing  about  a  response  by  the 
repetition  of  a  subliminal  stimulus  is  called  the  sum- 


40  GENERAL  PSYCHOLOGY 

mation  of  stimuli.  If,  for  example,  a  neighbor 
comes  at  night  and  persistently  knocks  on  a  man's 
door,  the  man  finally  rises  from  bed  and  lets  him  in, 
not  because  it  is  more  reasonable  to  do  so  now  than 
it  was  when  the  knocking  began,  but  because  of  the 
neighbor's  importunity. 

The  summation  of  stimuli  is  used  extensively  in 
advertising,  the  recurring  advertisement  often  lead- 
ing us  eventually  to  buy  the  article  described.  This 
accounts  in  part  for  the  number  of  people  who  use 
Ivory  Soap  and  Bull  Durham.  The  daily  sight  of 
the  unanswered  letter  in  the  letter  tray  may  finally 
call  forth  a  reply.  The  ingenious  torture  that  con- 
sisted in  allowing  a  series  of  drops  of  water  to  fall 
on  the  bound  victim  produced  a  summation  effect 
resulting  in  a  greatly  increased  response. 

Within  certain  limits  the  summation  effect  is  in- 
creased as  the  length  of  the  intervals  between  the 
subliminal  stimuli  is  diminished.  If  the  intervals 
are  lengthened  beyond  a  certain  point,  no  summation 
effect  occurs. 

A  response  is  sometimes  given  only  after  a  num- 
ber of  diverse  subliminal  stimuli  have  been  received, 
and  may  be  the  result  not  only  of  the  last  stimulus 
but  of  the  entire  series.  Bringing  about  a  response 
by  a  series  of  diverse  subliminal  stimuli  is  called 
the  summation  of  diverse  stimuli  The  prospective 
purchaser  of  an  automobile  is  led  to  visit  the  sales- 
room but  remains  irresolute  in  the  presence  of  the 
machine.    The  salesman  now  initiates  the  process  of 


THE  ELEMENTS  OF  BEHAVIOR         41 

summation.  He  calls  the  man's  attention  to  various 
good  features  of  the  machine,  and  each  of  these 
stimuli  brings  the  man  nearer  to  parting  with  his 
money.  The  salesman  appeals  to  his  customer's 
vanity  by  reference  to  prominent  men  who  own  that 
make  of  machine.  Finally  a  stimulus  is  given,  such 
as  the  assurance  that  after  this  car  is  sold  none  will 
be  available  for  several  months,  and  the  purchaser 
makes  out  his  check. 

To  induce  a  child  to  take  medicine,  the  summation 
of  diverse  stimuli  is  often  effective.  If  a  promise  of 
candy  or  of  money  does  not  have  results,  we  may 
try  such  bribery  as  offering  to  take  him  to  the  thea- 
ter, or  we  may  threaten  to  leave  him  at  home. 
Finally,  by  petting  or  cajolery,  the  summation  is 
completed.  We  often  describe  a  person  as  being 
favorably  disposed  toward  a  certain  course  of  action. 
This  usually  means  that  he  has  already  received  the 
first  few  of  a  series  of  diverse  stimuli  and  all  that  we 
need  do  is  to  complete  the  series  in  order  to  bring 
about  the  response.  For  example,  a  man's  child 
may  have  died  recently  and  we  realize  that  the  time 
is  auspicious  for  asking  him  to  contribute  to  a  chil- 
dren's charity.  The  acquaintance  whom  we  would 
greet  casually  at  home  is  welcomed  effusively  in  a 
foreign  country  because  we  are  already  stimulated 
to  friendliness  by  the  internal  changes  that  in  part 
constitute  homesickness. 

The  response  to  a  series  of  stimuli  varies  accord- 
ing to  the  order  in  which  the  stimuli  occur.    A  man 


42  GENERAL  PSYCHOLOGY 

standing  beside  a  dark  road  responds  differently  to 
the  sounds  of  approaching  footsteps  and  to  the 
sounds  of  retreating  footsteps,  which  may  be  exactly 
the  same  sounds  occurring  in  opposite  order. 
Royce  pointed  out  that  it  makes  a  difference 
whether  a  stranger  first  steps  on  a  man's  foot  and 
then  apologizes,  or  first  apologizes  and  then  steps 
on  a  man's  foot. 

Weber's  Law 

Within  certain  limits  the  intensity  of  a  stimulus 
may  vary  without  modifying  the  nature  of  the  re- 
sponse. If  the  stimulus  is  increased  or  decreased 
beyond  these  limits,  the  response  alters  its  charac- 
ter or  its  energy.  The  amount  by  which  a  stimulus 
must  be  increased  or  decreased  in  intensity  in  order 
to  alter  the  response  is  called  the  differential  thresh- 
old. This  term  should  not  be  confused  with  liminal 
threshold. 

About  1825  it  was  suggested  by  Weber,  a  German 
investigator,  that  the  ratio  of  the  differential  thresh- 
old to  the  amount  of  the  stimulus  is  constant  at  all 
intensities  for  each  class  of  stimuli.10  Although  the 
law  does  not  hold  for  very  weak  or  for  very  intense 
stimuli,  it  has  proven  a  demonstrable  and  valuable 
generalization.  The  ratio  differs  with  different 
kinds  of  stimulation,  being,  for  example,  smaller 
in  the  case  of  light  than  in  that  of  sound. 

10  For  a  more  detailed  account  of  Weber's  Law  see  Ladd  and 
Woodwortb,  op.  cit.,  pp.  361ff  and  374ff. 


THE  ELEMENTS  OF  BEHAVIOR         43 

The  reflected  light  from  a  candle  introduced  into 
a  sunlit  room  may  not  be  noticed,  but  such  an  in- 
crease of  illumination  in  twilight  is  at  once  appar- 
ent. It  may  be  impossible  to  distinguish  between  a 
pitch  of  512  vibrations  and  one  of  513,  but  easy  to 
hear  the  difference  between  pitches  of  32  and  33 
vibrations.  A  weight  of  80  grams  and  one  of  82 
grams  may  be  reported  as  being  the  same,  but  a 
weight  of  20  grams  and  one  of  22  will  probably  be 
recognized  as  different.  It  is  evident  that  the  ap- 
parent difference  between  two  lights  does  not  de- 
pend so  much  upon  the  absolute  difference  between 
the  stimuli  as  upon  the  proportion  of  this  differ- 
ence to  the  intensity  of  the  light.  An  absolute  dif- 
ference between  two  sound  intensities  does  not  in- 
sure our  distinguishing  between  the  two,  for  if  the 
intensities  are  great  this  difference  may  be  inade- 
quate. The  same  is  true  of  two  weights,  which  stim- 
ulate us  to  different  responses  only  if  one  is  about 
three  per  cent  heavier  than  the  other.  The  just 
noticeable  difference  for  light  is  about  one  per  cent 
of  the  intensity  of  the  stimuli.  These  differential 
thresholds  vary  greatly  with  different  subjects  and 
hold  only  within  a  limited  range  of  intensities. 

The  Interaction  of  Stimulus-Response  Mechanisms 

As  no  animal  is  ever  acted  upon  by  just  one  stimu- 
lus at  a  time,  but  at  any  given  moment  is  exposed 
to  a  great  complexity  of  stimuli,  its  resulting  be- 


44  GENERAL  PSYCHOLOGY 

havior  is  the  interplay  of  many  responses.  The  ac- 
tion of  any  stimulus  depends  on  the  other  stimuli 
that  occur  along  with  it.  A  loud  sound  heard  on 
the  city  streets  causes  a  response  different  from 
that  given  to  the  same  sound  when  the  hearer  is 
alone  in  the  woods. 

The  combination  of  all  the  stimuli  to  which  an  ani- 
mal responds  at  any  moment  is  called  a  situation, 
and  a  combination  of  responses  is  called  an  act.11 

If  the  situation  that  confronts  the  animal  tends  to 
arouse  simultaneously  two  stimulus-response  mech- 
anisms, there  may  occur  one  of  two  results.  One 
of  the  mechanisms,  though  not  itself  responding,  may 
increase  the  tendency  of  the  other  to  respond;  or 
one  may  interfere  with  the  action  of  the  other. 

The  first  of  these  results,  where  one  system  is  an 
aid  to  the  other,  is  called  facilitation.  This  aid  or 
reenforcement  produces  a  more  lively  response  in 
the  system  that  is  facilitated.  Suppose  a  man,  see- 
ing a  bear  in  the  woods,  responds  by  a  dignified  re- 
treat. The  bear  now  moves  in  the  man's  direction 
and  he,  previously  walking,  breaks  into  a  run.  Pigs 
eat  more  greedily  when  other  pigs  are  sharing  the 
meal,  and  almost  any  animal  will  partake  more  rap- 
idly of  the  food  that  we  threaten  to  remove.  A 
toothache  ends  our  delay  in  visiting  the  dentist,  and 
a  good  appetite  makes  us  respond  promptly  when 
summoned  to  dinner. 

n  These  definitions  are  proposed  by  Watson,  Psychology  from  the 
Standpoint  of  a  Behaviorist,  p.  10. 


THE  ELEMENTS  OF  BEHAVIOR         45 

An  increased  tendency  to  act  is  to  be  expected 
when  two  stimuli  lead  to  the  same  response,  but 
this  increased  tendency  may  also  occur  in  cases 
where  the  responses  produced  by  the  two  stimuli 
are  not  the  same. 

The  difference  between  facilitation  and  the  sum- 
mation of  stimuli  lies  in  this,  that  the  stimuli  com- 
bined in  summation  are  all  subliminal  and  occur 
serially,  whereas  the  stimuli  combined  in  facilitation 
may  or  may  not  be  subliminal  and  if  subliminal  must 
occur  simultaneously. 

Contrasted  with  facilitation  is  the  case  of  inter- 
ference between  two  stimulus-response  mechanisms. 
As  a  result  of  interference  three  things  may  hap- 
pen; either  both  responses  are  given  with  lessened 
energy,  or  one  response  is  given  with  lessened  en- 
ergy and  the  other  is  not  given,  or  neither  response 
occurs.  The  hampering  effect  that  one  system  has 
upon  another  is  called  distraction.  The  preventing 
effect  that  one  system  has  upon  another  is  called 
inhibition.  If  a  trap  is  baited  and  an  animal  is  led 
by  the  odor  of  the  bait  to  approach  the  trap,  and  if 
there  is  no  odor  of  man  about  the  trap,  the  animal 
will  seize  the  bait  and  be  caught.  If,  however,  the 
body  odor  of  the  trapper  adheres  to  the  trap,  the 
animal  will  either  take  the  bait  less  readily  or  will 
entirely  disregard  it.  If  the  bait  is  taken  reluctantly, 
the  body  odor  is  a  distracting  stimulus ;  and  if  it  is 
not  taken  at  all,  the  body  odor  is  an  inhibiting 
stimulus. 


46  GENERAL  PSYCHOLOGY 

The  reason  one  response  prevails  over  the  other  is 
either  that  there  is  more  resistance  in  the  conduc- 
tion path  of  one  system  than  in  that  of  the  other, 
or  that  the  relative  strength  of  the  two  stimuli  in 
terms  of  their  thresholds  is  different.12 

When  interference  so  raises  the  threshold  of  both 
responses  that  neither  is  given,  we  have  mutual  in- 
hibition. In  this  case  a  third  stimulus  may  bring 
about  a  response  that  removes  the  animal  from  the 
first  two  stimuli,  and  the  interference  disappears. 
This  may  be  seen  in  the  case  of  a  man  who  is  ad- 
dressed by  someone  while  he  is  reading.  He  pauses 
in  his  reading  and  it  is  now  doubtful  whether  he  will 
answer  the  questioner  or  resume  his  book.  One  of 
these  responses  will  eventually  be  given  unless  a 
third  stimulus,  such  as  the  ringing  of  the  telephone, 
causes  him  to  disregard  both  book  and  questioner. 
Ordinarily  man  is  acted  upon  not  by  two  but  by  a 
multiplicity  of  stimuli,  and  his  responses  are  de- 
termined by  facilitating  stimuli,  inhibiting  stimuli, 
distracting  stimuli,  and  by  the  stimuli  that  primar- 
ily elicit  the  response. 

Compromise  Eesponses 

When  a  spinal  dog  is  simultaneously  stimulated 
at  a  point  on  the  shoulder  and  at  a  point  several 
inches  farther  back,  he  scratches  a  spot  somewhere 

12  For  a  discussion  of  the  neural  basis  of  interference,  see  Sher- 
rington, op.  cit.,  pp.  55,  115-149,  223. 


THE  ELEMENTS  OF  BEHAVIOR         47 

between  the  two.  His  response  is  in  the  nature  of 
a  compromise.  Man,  as  well,  when  stimulated  to 
two  distinct  responses,  often  acts  in  a  way  that  is 
a  resultant  of  the  two  response  tendencies.  When 
playing  ball  with  a  stone,  we  tend  to  throw  it  as  if 
it  were  a  ball  to  the  person  who  is  about  to  catch  it, 
and  we  tend  to  refrain  from  throwing  it  because 
we  are  in  the  habit  of  not  stoning  our  friends.  The 
resultant  act  consists  in  throwing  the  rock  gently. 

Compromise  in  emotional  responses  is  the  rule 
rather  than  the  exception.  If  a  child's  mischief  an- 
noys us,  we  respond  to  him  both  as  to  a  child  to  be 
treated  kindly  and  as  to  a  nuisance  to  be  abated. 
The  resultant  response  is  remonstrance  with  sad 
good  humor.  When  a  puppy  is  scolded,  his  behavior 
is  a  compromise  between  affection  and  fear,  and  is 
somewhat  suggestive  of  the  politeness  of  human 
beings  in  the  presence  of  strangers. 


CHAPTER  II 


INSTINCT 


If  we  know  the  structure  of  a  machine,  we  can 
predict  what  it  will  do  whenever  it  is  acted  upon 
in  a  familiar  way.  Man  is  no  exception  to  the  rule, 
and  we  find  that  in  so  far  as  men  are  alike  in  struc- 
ture they  respond  in  the  same  way  whenever  their 
sense  organs  are  acted  upon  in  a  like  manner. 
Babies  all  show  a  great  similarity  of  structure  at 
birth  before  they  begin  to  learn,  and,  to  a  consid- 
erable extent,  this  similarity  of  structure  persists 
when  they  become  adults,  and  even  after  each  has 
taken  on  individual  peculiarities  due  to  the  particu- 
lar influences  to  which  he  has  been  exposed. 

In  addition  to  this  partial  persistence  of  the  baby's 
original  nature,  there  is  a  closely  related  factor  that 
helps  to  make  all  men  somewhat  alike.  This  is  that 
the  structures  of  all  of  us  tend  to  change  in  the 
same  way  as  we  grow  older.  This  change  we  call 
maturation. 

Acts  that  are  due  to  original  structure,  or  due  to 
a  structure  resulting  from  simple  maturation,  we 
call  instincts.    Such  a  definition  as  this  makes  it  pos-^ 
sible  to  describe  all  behavior  as  either  instinctive  or 
learned. 

48 


INSTINCT  49 

Reflexes 

Spinal  reflexes  have  been  described  in  Chapter  I. 
Man's  original  structure  includes  most  spinal  reflex 
arcs,  and,  in  addition  to  these,  many  neural  arcs  of 
greater  complexity  whose  pathways  involve  connect- 
ing fibres  in  the  medulla  and  brain.  All  these  natural 
pathways  through  the  brain  are  usually  called  re- 
flex arcs  of  higher  level.  The  fixation  of  a  light 
that  has  fallen  on  the  periphery  of  the  retina,  and 
the  grimacing  due  to  a  bitter  substance  on  the  tongue 
are  examples  of  such  higher  level  reflexes. 

A  baby  that  is  just  born  is  almost  wholly  lacking 
in  experience.  Although  for  some  time  before  birth 
the  sense  organs,  the  nervous  system,  and  the 
muscles  are  sufficiently  mature  to  function,  a  con- 
clusion that  is  proved  by  the  behavior  of  premature 
infants,  the  child's  isolation  and  confinement  pre- 
vent any  very  elaborate  responses. 

At  birth  the  infant  enters  a  world  rich  in  situa- 
tions, and  a  world  permitting  freedom  of  movement. 
Then  for  the  first  time  he  experiences  light,  odor, 
temperature,  and  cutaneous  pain  stimuli.  He  then 
draws  his  first  breath,  cries,  swallows,  coughs, 
sneezes,  nurses,  and  fixates  objects  with  his  eyes.  He 
is  still  a  creature  of  reflexes,  although  some  of  these 
reflexes,  such  as  the  movements  of  nursing,  occur  in 
fairly  predictable  series. 

Many  careful  observations  and  experiments  have 
been  made  upon  babies  from  birth  in  order  to  dis- 


50  GENERAL  PSYCHOLOGY 

cover  the  nature  of  their  reflex  responses.1  The 
maternity  hospital  affords  excellent  opportunity  for 
this  work  during  the  first  few  weeks  of  the  baby's 
life.  Movements  made  by  an  infant  at  birth  may  be 
regarded  as  natural  tendencies  unaffected  by  habit 
formation.  In  the  case  of  responses  made  after  a 
baby  is  several  weeks  old,  even  though  they  are  then 
performed  for  the  first  time,  there  is  always  a  pos- 
sibility that  they  are  a  product  of  training,  although 
often  it  seems  more  plausible  to  regard  them  as 
natural  tendencies  that  are  the  outcome  of  simple 
maturation.  The  ability  of  a  baby  to  reach  out  and 
grasp  an  object  that  he  sees,  usually  appears  when 
he  is  four  or  five  months  old.  It  is  uncertain 
whether  this  act  is  due  wholly  to  the  maturation  of 
his  nervous  system  or  is  the  result  of  trial  and 
error  learning.  Before  this  so-called  eye-hand  co- 
ordination is  attained,  he  has  grasped  many  objects 
that  come  in  contact  with  the  palm  of  his  hand  and 
has  fixated  these  objects  with  his  eyes.  Whether 
or  not  this  act  is  instinctive  could  be  decided  only 
by  placing  the  child  in  such  restraint  that  no  experi- 
ence in  casual  grasping  would  be  possible.  If,  on 
being  given  his  freedom  at  the  proper  time,  the 
eye-hand  coordination  at  once  occurred,  we  could 
assign  it  with  certainty  to  the  category  of  reflex. 
The  suddenness  with  which  this  and  other  coordi- 
nated movements  appear,  however,  lends  plausibility 


1  Watson,  Psychology  from  the  Standpoint  of  a  Behaviorist,  chap. 
6  and  7. 


INSTINCT  51 

to  the  assumption  that  such  acts  are  dependent  upon 
late  maturation  and  are  to  some  extent  independent 
of  training. 

Just  after  a  baby  is  born,  and  when  he  begins  to 
breathe,  a  vocalization  known  as  the  birth  cry  occurs. 
This  cry  is  elicited  by  asphyxia  and  the  customary 
slapping.  Yawning  has  been  observed  five  minutes 
after  birth,  and  sneezing  sometimes  occurs  as  soon 
as  the  baby  is  born.  Blanton2  describes  the  "  colic 
cry"  as  being  high  pitched  and  different  in  this 
respect  from  the  general  crying  due  to  hunger,  pain, 
and  fatigue.  Crying  in  response  to  a  cold  plunge 
may  be  inspiratory  in  character.  Drawing  down 
the  corners  of  the  mouth  while  crying  has  been  ob- 
served 30  minutes  after  delivery,  and  the  trans- 
verse crease  between  the  eyes  may  occur  at  birth. 
Being  picked  up  may  cause  the  baby  to  cry,  and  a 
surgical  operation  will  at  any  time  cause  this  re- 
sponse. 

Blanton  reports  the  following  sounds  during  the 
first  month :  m,  n,  ng,  h,  w,  r,  y,  ow  as  in  owl,  ee  as  in 
feel,  oo  as  in  pool,  a  as  in  an,  and  a  as  in  father. 

The  enteric  responses  given  the  first  day  are  swal- 
lowing, hiccoughing,  regurgitation,  spitting  out, 
sucking,  licking,  and  defecation. 

Binocular  accommodation  and  fixation  of  a  light 
are  often  to  be  observed  during  the  first  hour.  Fixa- 
tion is  most  easily  elicited  when  the  light  is  placed 


2  Blanton.  "Behavior  of  the  Human  Infant,"  Psychological  Review, 
1917,  pp.  456-483. 


52  GENERAL  PSYCHOLOGY 

directly  in  front  of  the  child.  Blanton  reports  that 
the  eyes  of  many  babies  follow  a  slow  moving  hand 
at  birth.  Watson  observed  no  blinking  in  response 
to  a  threatening  gesture  prior  to  the  fifty-fifth  day. 
The  head  may  be  rotated  toward  the  source  of  light 
during  the  first  few  days.  Tears  may  be  present 
from  birth. 

Smiling  has  been  observed  in  babies  as  young  as 
four  days  old  and  may  result  from  tickling  on  the 
face,  stroking  other  parts  of  the  body,  rocking,  or  be- 
ing turned  on  the  abdomen  across  the  nurse's  knee. 

In  response  to  sound,  the  child  may  start,  squirm, 
cry,  or  awaken  from  sleep  any  time  after  birth. 

If  placed  face  down  upon  a  flat  surface,  the  baby 
may  rotate  the  head  a  half  hour  after  birth.  Ac- 
cording to  Blanton  practically  all  babies  three  days 
of  age  will  raise  the  head  when  the  face  is  buried  in 
a  pillow.  When  held  in  a  sitting  posture,  the  baby 
may  hold  its  head  in  equilibrium  after  the  second 
or  third  day. 

Finger  movements  may  be  observed  at  birth,  and 
the  grasping  reflex  is  sufficiently  strong  from  this 
time  on  to  make  it  possible  for  the  infant  to  sup- 
port its  body  weight  when  holding  to  a  rod.  This 
muscular  contraction  is  due  to  cutaneous  stimulation 
of  the  palms,  and  to  stretching  of  the  tendons.  The 
response  is  most  energetic  in  the  case  of  a  crying 
child. 

At  any  time  after  birth,  when  the  child  is  dropped, 
the  arms  are  thrown  up  toward  the  head.    When  the 


INSTINCT  53 

head  is  being  scrubbed  shortly  after  birth,  the  in- 
terference of  the  baby's  hand  sometimes  interrupts 
the  process.  Watson,  on  taking  hold  of  the  nose  of 
a  three-day  old  baby,  found  that  the  child's  hands 
almost  immediately  engaged  his  fingers.  Avoidance 
movements  of  the  arms  may  be  elicited  in  very  young 
infants  by  gentle  pricking  of  the  wrist.  Kicking  is 
commonly  aroused  by  the  clamping  and  tying  of  the 
umbilical  cord. 

Blanton  found  that  dropping  alcohol  on  either  side 
of  the  abdomen  elicited  a  leg  movement  on  the  side 
stimulated.  She  reports  that  when  the  big  toe  is 
pricked  to  secure  a  specimen  of  blood,  the  other  foot 
is  drawn  up  and  pressed  against  the  ankle  of  the 
pricked  side.  Watson  found  that  when  an  infant  at 
five  days  of  age  is  pinched  on  the  inner  surface  of  the 
knee,  the  other  heel  will  be  brought  up  to  this  spot. 

Stretching  and  arching  in  response  to  removal  of 
clothing  has  been  observed  on  the  twenty-fifth  day. 
Shivering  may  occur  shortly  after  birth  and  the  toes 
may  be  curled  when  the  feet  are  exposed  to  the 
warmth  of  a  fire  when  the  child  is  a  few  days  old. 

If  a  baby  is  suddenly  lowered,  in  addition  to  the 
upward  movement  of  the  arms,  there  is  elicited 
grasping  and  holding  the  breath.  Another  coordi- 
nated movement  that  may  occur  during  the  first  few 
days  is  turning  over  after  being  placed  face  down. 
Creeping  backward  may  occur  during  the  second 
week,  but  the  change  of  position  is  very  slight.  Blan- 
ton records  in  the  case  of  one  baby  two  hours  old  the 


54  GENERAL  PSYCHOLOGY 

repeated  act  of  placing  the  hand  in  the  mouth.  The 
youth  of  the  child  would  indicate  this  to  be  an  in- 
stinctive mechanism. 

Watson  found  no  tendency  on  the  part  of  a  baby 
of  169  days  to  wipe  its  hands  when  given  a  ball  of 
library  paste.  If  hand  wiping  is  an  instinct,  which 
may  be  doubted,  it  matures  at  a  later  period.  The 
same  experimenter  could  elicit  no  swimming  move- 
ments from  young  infants,  which  contradicts  the 
accounts  of  the  recapitulationists. 

Some  of  Watson's  observations  of  emotional  re- 
sponses may  be  stated  here.  Blinking  and  an  up- 
ward movement  of  the  hands  were  elicited  at  100 
days  in  response  to  a  threatening  gesture.  Crying 
followed  loud  sounds  or  the  jerking  of  the  baby's 
blanket.  No  fear  responses  were  given  by  the  165- 
day  old  baby  to  the  sight  or  handling  of  a  cat,  a  rab- 
bit, or  a  pigeon.  Rage  responses,  consisting  of 
stiffening  the  body,  holding  the  breath,  thrashing 
with  arms  and  legs,  and  screaming,  were  produced 
by  hampering  the  infant's  movements  or  by  simply 
holding  the  arms  or  head. 

Instincts  are  Chain  Reflexes 

No  response  is  ever  given  that  does  not  in  turn 
cause  the  stimulation  of  some  sense  organ.  The  con- 
traction of  a  muscle  stimulates  the  muscle  spindles 
that  are  contained  in  it.  The  secretion  of  saliva  or 
tears  stimulates  adjacent  touch  organs.    Vocaliza- 


INSTINCT  55 

tion  stimulates  the  ear  of  the  person  who  makes  the 
sound  as  well  as  the  proprioceptors  in  the  contract- 
ing muscles.  Scratching,  clenching  the  fist,  sneez- 
ing, winking,  swallowing,  breathing,  or  a  response 
of  any  sort  whatever,  produces  its  characteristic 
stimulus.  Stimuli  furnished  by  responses  are  called 
movement-produced  stimuli. 

Many  responses  cause  new  stimuli  from  the  ex- 
ternal world  to  act  upon  us.  If  we  open  our  eyes, 
turn  our  head,  touch  the  stove,  walk  from  place  to 
place,  open  a  book,  light  a  cigar,  or  call  to  a  passer- 
by, the  act  itself  is  productive  of  new  stimuli.  These 
stimuli  from  the  external  world  that  result  from  re- 
sponses are  also  called  movement-produced  stimuli. 

Movement-produced  stimuli  in  their  turn  result  in 
movements,  and  these  movements  cause  further  stim- 
ulation. In  this  way  a  chain  of  reflexes  once  begun 
may  maintain  itself  by  its  own  movement-produced 
stimuli.  When  the  chain  of  stimuli  are  within  the 
body,  the  order  of  the  responses  is  highly  predict- 
able. This  is  because  the  structure  of  the  body  is 
fairly  stable.  A  person  who  begins  to  yawn  always 
finishes  because  the  muscle  strain  of  the  first  part 
of  the  act  causes  the  movements  that  complete  the 
series.  No  one  stops  with  an  open  mouth  and  fails 
to  finish  his  yawn.    (See  Figure  13.) 

When  movements  bring  stimuli  from  the  external 
world  to  bear  upon  us,  the  chain  of  reflexes  that  re- 
sults is  predictable  if  the  external  situation  is  famil- 
iar and  common.    Man   is   strikingly   adjusted  to 


56  GENERAL  PSYCHOLOGY 

any  of  these  commonly  recurring  situations  in  that 
his  responses  cause  changes  in  the  external  world 
necessary  to  his  preservation. 

Suckling  is  a  chain  of  reflexes,  each  reflex  being 
called  out  by  the  stimulus  that  the  preceding  re- 
sponse produces.  If  a  baby  is  gently  tickled  on  the 
side  of  the  mouth  or  on  the  cheek,  its  head  is  moved 
so  as  to  engage  the  stimulating  object  with  its  mouth. 


*       Y       W*'        Sr       Wfi 


Figure  13.  diagrammatic  representation  of  the  chain  reflex 
mechanism  (after  herrick).  c,  synapses  in  nerve  centers, 
e,  effectors.  r,  receptors.  the  action  of  each  effector  results 
in  the  stimulation  of  an  adjacent  receptor.  the  stimulation 
of  each  receptor  results  in  the  action 
of  an  effector 


This  is  a  reflex.  In  finding  the  breast  the  baby  is 
thus  guided  by  the  erectile  mamilla.  The  mamilla 
in  his  mouth  is  the  stimulus  to  reflex  movements  of 
the  neck,  jaws,  tongue,  and  lips  that  cause  close  con- 
tact with  the  breast  and  produce  suction.  These 
movements  result  in  milk's  entering  the  mouth. 
When  milk  is  taken  into  the  mouth,  it  is  the  stimulus 
to  reflex  swallowing. 

It  will  be  seen  that  each  step  in  the  series  of  nurs- 
ing movements  is  an  act  of  intervention  that  brings 
about  the  stimulus  for  the  next  movement.  Each 
step  may,  however,  be  elicited  independently  by  the 
proper  stimulus.    Any  touch  on  the  cheek  may  cause 


INSTINCT  57 

the  mouth  to  engage  the  stimulating  object.  Any- 
thing placed  between  the  lips  may  cause  reflex  suck- 
ing. Any  fluid  in  the  mouth  may  cause  swallowing. 
That  these  acts  are  called  forth  in  the  proper  series 
depends  upon  the  presence  of  a  nursing  mother. 
She  is  the  ubiquitous  situation  to  which  all  babies  are 
adjusted. 

If  movement-produced  stimuli  alone  caused  the 
baby's  next  reaction,  he  would  lose  his  way  in  the 
world  and  perish.  Fortunately,  however,  he  is 
guided  by  a  world  of  orderly  events.  Conversely, 
if  the  baby  had  no  original  organization  to  deter- 
mine in  part  the  sequence  of  reactions,  the  baby,  by 
trial  and  error  learning,  would  have  to  establish 
the  order  of  the  minute  parts  of  all  the  serial  re- 
sponses necessary  for  his  survival  from  birth. 
Otherwise  he  could  live  only  in  situations  that  would 
call  out  in  the  proper  order  the  parts  of  each  re- 
sponse. That  one  response  may  lead  to  another  with- 
out learning,  and  guided  chiefly  by  movement-pro- 
duced stimuli,  is  well  illustrated  in  some  of  the  co- 
ordinated movements  of  newborn  animals. 

The  baby's  endowment  consists  of  relatively  sim- 
ple mechanisms,  with  fewer  instinctive  responses  to 
movement-produced  stimuli  than  are  found  in  most 
of  the  lower  animals.  Compared  with  the  wasp, 
which  flies,  stings,  and  secures  its  own  food  from 
the  time  it  leaves  its  cell,  the  baby  has  much  to  learn. 
It  is  here  that  the  child's  capacity  for  learning  com- 
pensates for  his  early  helplessness,  and  secures  for 


58  GENERAL  PSYCHOLOGY 

him  in  the  end  an  integration  of  behavior  much  more 
elaborate  than  that  of  an  insect.  The  number  as 
well  as  the  simplicity  of  the  responses  that  are  ready 
to  be  attached  to  the  child's  private  environment  and 
to  the  stimuli  that  his  own  movements  provide,  con- 
tributes to  this  ultimate  superiority. 

Whereas  the  lower  animals,  in  response  to  any 
one  of  a  number  of  stimuli,  make  the  same  elabo- 
rately coordinated  movement  involving  many  effec- 
tors, the  baby  responds  to  each  stimulus  with  a  sim- 
pler bodily  movement,  but  with  a  movement  more 
particularly  reserved  for  that  element  of  the  situa- 
tion. In  this  way  the  behavior  of  the  human  infant 
exhibits  frequent  incongruities  and  combinations  of 
reaction  that  interfere  with  one  another.  Gradually 
his  responses  are  coordinated  and  adjusted  to  his 
world  in  a  fashion  that  will  be  described  under  the 
heading  Shortening  of  a  Trial  and  Error  Series. 

Thus  the  instincts  of  babies  are  more  numerous 
and  less  complex  than  are  the  instincts  of  the  young 
of  other  species.  Human  beings  are  not  endowed 
with  ready- formed  tendencies  to  fight,  hunt,  swim,  or 
build  shelter.  These  elaborate  instincts  in  lower 
animals  are  due  to  many  definite  reflex  responses  to 
movement-produced  stimuli.  All  such  acts  in  man 
are  learned.  Even  putting  out  the  hand  and  grasp- 
ing an  object  may  be  an  art  acquired  by  trial  and 
error.  Suckling  and  the  emotional  responses  are  the 
most  elaborate  of  man's  instinctive  chain  reflexes. 
The  movements  involved  in  these  acts  are  stereo- 


INSTINCT  59 

typed  in  order  and  in  kind,  and  these  action  patterns 
maintain  in  large  part  their  integrity  throughout 
life. 

Mr.  and  Mrs.  Peckham  have  described  an  interest- 
ing chain  reflex  (instinct)  of  a  solitary  wasp,  as  fol- 
lows : 3 

She  worked  for  an  hour,  first  filling  the  neck  of  the 
burrow  with  fine  earth  which  was  jammed  down  with 
much  energy — this  part  of  the  work  being  accompanied 
by  a  loud  and  cheerful  (sic)  humming — and  next  arrang- 
ing the  surface  of  the  ground  with  scrupulous  care,  and 
sweeping  every  particle  of  dust  to  a  distance.  Even  then 
she  was  not  satisfied,  but  went  scampering  around,  hunting 
for  some  fitting  object  to  crown  the  whole.  First  she  tried 
to  drag  a  withered  leaf  to  the  spot,  but  the  long  stem  stuck 
in  the  ground  and  embarrassed  her.  Relinquishing  this, 
she  ran  along  a  branch  of  the  plant  under  which  she  was 
working  and,  leaning  over,  picked  up  from  the  ground 
below  a  good-sized  stone;  but  the  effort  was  too  much  for 
her,  and  she  turned  a  somersault  on  to  the  ground.  She 
then  started  to  bring  a  large  lump  of  earth;  but  this  evi- 
dently did  not  come  up  to  her  ideal,  for  she  dropped  it 
after  a  moment,  and  seizing  another  dry  leaf  carried  it 
successfully  to  the  spot  and  placed  it  directly  over  the  nest. 

An  important  fact  in  the  behavior  of  any  animal 
is  that  it  persists  in  what  it  is  doing  up  to  a  certain 
point  and  then  turns  to  something  else.  The  wasp 
responds  to  the  various  small  objects  in  the  neigh- 
borhood by  attempting  to  drag  them  to  the  hole, 

3  G.  W.  and  E.  G.  Peckham,  Wasps,  Social  and  Solitary,  Boston, 
1905. 


60  GENERAL  PSYCHOLOGY 

and  then  desists  when  the  hole  is  covered.  The  baby 
responds  by  well  established  reflexes  to  objects  touch- 
ing his  cheek,  to  -anything  inserted  between  his  lips, 
and  to  fluid  in  his  mouth,  until  his  hunger  is  dis- 
sipated. In  these  cases,  covering  the  hole  and  fill- 
ing the  stomach  are  called  consummatory  responses. 
Although  reflexes  may  be  classified  according  to 
the  stimuli  that  call  them  forth,  or  according  to  the 
responses  that  result,  such  a  classification  is  impos- 
sible when  we  deal  with  *an  instinct  that  is  a  chain  of 
reflexes.  This  is  because  the  chain  of  reflexes  does 
not  always  follow  a  fixed  order,  excepting  in  that 
it  is  terminated  by  a  characteristic  response.  It  is 
in  terms  of  these  final  responses  that  instincts  are 
classified. 

Precurrent  and  Consummatory  Responses 

When  we  attempt  to  describe  what  an  animal  is 
doing,  we  find  that  we  can  distinguish  between  cer- 
tain responses  that  mark  the  end  of  a  series  of  acts 
and  those  that  lead  up  to  this  final  response.  We 
may  see  a  dog  running  about  in  a  field,  occasionally 
picking  up  a  scent  and  f ollowing  it,  losing  the  scent, 
ranging  about  until  it  is  recovered,  and  barking,  all 
with  evident  excitement.  We  explain  his  behavior 
by  saying  that  he  is  after  a  rabbit,  although  it  is  evi- 
dent that  the  rabbit  itself  is  not  acting  as  a  visual 
stimulus.  One  of  the  important  stimuli  for  the  dog's 
activity  is  the  scent  the  rabbit  leaves  behind  it.    The 


INSTINCT  61 

odor  prompts  the  dog  to  follow  the  trail  with  his 
nose  to  the  ground,  and  arouses  energetic  emotional 
responses.  A  part  of  the  movements  that  would  be 
involved  in  seizing  the  rabbit  are  also  present,  but 
the  act  of  seizing  can  not  be  entirely  carried  out  be- 
cause there  is  no  rabbit  near  enough  to  be  seized. 
That  the  stimuli  that  cause  the  dog  to  hunt  are  in 
part  internal  stimuli,  is  shown  by  the  faet  that  this 
behavior  appears  whenever  the  dog  has  been  for  a 
time  without  food. 

The  response  that  puts  an  end  to  this  activity  is 
killing  and  devouring  the  rabbit.  The  reason  that 
the  activity  ends  is  that  the  internal  stimuli  that 
prompted  the  animal  to  range  about  have  been  re- 
moved by  the  act  of  eating. 

Many  responses  are  of  such  a  nature  that  they 
bring  to  an  end  the  stimuli  that  caused  them.  Often, 
when  a  response  is  prevented,  emotional  reinforce- 
ment ensues,  so  that,  when  the  stimulus  is  persistent 
or  recurrent,  negative  adaptation  toward  it  does  not 
occur.  This  emotional  reenforcement  makes  prob- 
able the  occurrence  of  the  response  as  soon  as  a 
change  in  the  situation  allows  it.  Such  a  stimulus 
may  act  throughout  a  long  period,  during  which  it 
interferes  with  responses  to  many  other  stimuli. 
Persistent  or  recurring  stimuli  whose  responses  are 
blocked  with  a  resulting  emotional  reenforcement 
will  be  called  maintaining  stimuli.  Maintaining 
stimuli  are  ultimately  removed  by  the  responses  they 
themselves  provoke. 


62  GENERAL  PSYCHOLOGY 

The  final  response  that  removes  these  maintaining 
stimuli,  by  altering  either  the  external  situation  or 
the  internal  state  of  the  animal,  is  called  a  consum- 
matory response.  The  series  of  responses  leading 
up  to  this  final  response  are  called  precurrent  re- 
sponses. 

Precurrent  responses  are  governed,  for  the  most 
part,  by  the  external  situation.  When  a  dog  is  hun- 
gry, the  details  of  his  behavior  are  his  responses, 
instinctive  or  learned,  to  the  circumstances  in  which 
he  finds  himself.  The  odor  of  rabbit  causes  ranging 
about,  and  in  the  case  of  a  dog  that  has  once  caught 
a  rabbit,  the  odor  arouses  eating  movements  in  so 
far  as  they  may  be  given  in  the  absence  of  food. 

These  eating  movements,  a  part  of  the  consum- 
matory  response,  are  interestingly  shown  by  a  dog 
or  a  horse  when  inaccessible  food  is  displayed.  Prob- 
ably a  part  of  the  consummatory  response  is  always 
given  throughout  the  period  of  preparatory  acts, 
and  this  maintains  a  low  threshold  for  the  consum- 
matory response  until  the  opportunity  for  giving  it 
in  its  entirety  arrives.  The  organs  of  response  in- 
volved in  a  consummatory  reaction  are  thus  in  a 
state  suitable  for  use,  and  the  stimuli  produced  by 
this  making  ready  for  action  serve,  after  repeated 
experience,  to  bring  about  or  to  facilitate  the  pre- 
current responses.  This  state  of  readiness  in  ef- 
fectors may  be  observed  throughout  the  interval  be- 
tween arousal  and  consummation  in  such  acts  as 
mating,  hunting,  nest-building,  quarreling,  or  search- 


INSTINCT  63 

ing  for  a  lost  article.  It  is  this  that  makes  the  dog 
range  about  when  he  has  lost  the  scent,  with  the  re- 
sult that  the  scent  is  again  picked  up. 

When  the  trail  is  lost,  the  dog  is  left  with  an 
abortive  tendency  to  respond  to  an  odor  stimulus. 
This  results  in  an  emotional  reaction  that  reenforces 
the  trial  and  error  behavior  by  which  the  scent  is 
recovered. 

The  blocking  of  any  consummatory  response  ten- 
dency results  in  emotion,  and  this  resulting  emo- 
tion is  in  a  considerable  degree  proportional  to  the 
strength  of  the  blocked  tendency.  When  the  swim- 
mer finds  his  efforts  to  reach  shore  interfered  with 
by  the  current,  he  is  overtaken  by  panic.  If  you 
tell  a  child  that  you  have  something  in  your  pocket 
that  you  have  decided  not  to  show  him,  he  imme- 
diately becomes  excited.  Anyone  whose  efforts  to 
catch  a  train  are  interfered  with  becomes  emotion- 
ally wrought  up.  When  Shakespeare's  Anthony  told 
the  people  that  he  held  in  his  hand  a  document  that 
he  did  not  intend  to  read,  their  apathy  changed  to 
interest.  Any  object  whose  price  renders  our  pos- 
sessing it  impossible  becomes  by  that  fact  more  de- 
sirable. Hampering  anyone's  movements  results  in 
his  showing  rage.  Hunting  is  interesting  only  if  the 
game  is  difficult  to  secure.  This  emotional  reinforce- 
ment derived  from  the  postponement  of  the 
consummatory  response  serves  to  facilitate  the 
precurrent  responses  and  so  to  hasten  the  consum- 
mation. 


64  GENERAL  PSYCHOLOGY 

The  final  or  consummatory  response  in  any  ehain 
reflex  is  a  convenient  basis  for  classifying  instincts. 

Mating  behavior  is  always  terminated  when  copu- 
lation occurs.     Food-seeking  is  always  terminated 
by  eating.     Nest-building  ceases  when  the  nest  is 
finished.    Flight  continues  until  a  place  of  security 
is  reached.    Combat  ends  when  the  foe  is  killed  or 
routed.    The  body  is  scratched  until  the  parasite  is 
removed.    The  behavior  that  leads  up  to  these  con- 
summatory responses  varies  greatly  according  to 
the  situation,  but  the  consummatory  responses  them- 
selves are  highly  predictable  and  so  serve  as  a  basis 
for  the  classification  of  instincts.    Under  each  of  the 
following  important  consummatory  responses  will  be 
listed  a  number  of  chain  reflexes  to  illustrate  the 
variety  of  ways   in  which  diverse  precurrent  re- 
sponses lead  to  the  same  ultimate  result.    Probably 
few  of  these  response  series  are  purely  instinctive. 
Certainly,  in  the  case  of  man,  these  utilities  are 
served  for  the  most  part  by  learned  acts. 

Swallowing  Food 

Suckling  Striking  by  snakes 

Following  while  suckling  Striking  by  fish 

Mouth    gaping    by    young  Diving  by  birds 

birds  Stinging  and  sucking  by  in- 
Crying     and     whining     of         sects 

young  Grasping 

Licking  Constriction  by  snakes 

Scratching  the  ground  Biting 

Restlessness  due  to  hunger  Pecking 

Following  a  scent  Stalking 


INSTINCT 


65 


Tongue  movements  of  liz- 
ards and  frogs 

Chasing 

Creating  water  currents 

Seizure  due  to  contact 

Hunting  cry  of  owls  and 
lions 

Web  building 

Carrying  home  food 

Migration 

Crouching 

Lying  in  ambush 


Springing 

Lapping 

Chewing 

Grazing 

Rumination 

Fighting  and  intimidating 
possible  competitors 

Threatening  wing  move- 
ments of  pigeons  while 
eating 

Hunting  in  packs 


Copulation 


Preliminary  restlessness 
Mating  calls 
Drumming  by  partridge 
Strutting,  showing  off,  and 

dancing 
Coyness  of  females 
Fighting  among  males 


Nuptial   flight   of  some    in- 
sects 

Migration 

Courtship 

Affectionate     behavior 
ward  permanent  mate 


to- 


Securing  Shelter 


Restlessness  in  the  open 

Stereotropisms 

Retirement  to  shelter  in  re- 
sponse to  darkness 

Seeking  a  roost  high  above 
ground 

Burrowing  and  excavating 

Cocoon  spinning  and  the  use 
of  secretions  in  building 

Caterpillar's  use  of  leaves 
in  building 

Collecting  building  materials 


such  as  mud,  sticks,  leaves, 

hair 
Rearranging  these  into  nests 

and    dens,    in    trees,    on 

ground,  in  burrows 
Plucking  fur  and  down  from 

breast  for  lining  nest 
Dam  building  by  beavers 
Yarding  by  moose 
Huddling  by  cattle 
Cooperative  nest  building  of 

insects 


66 


GENERAL  PSYCHOLOGY 

Defeating  Antagonists 


Restlessness  when  alone  and 
seeking   company   of   fel- 
lows,   resulting  in   herds 
and  colonies 
Secretions  of  skunk 
Discharge  of  nematocysts 
Taking    up    posture    which 
makes    the    animal    seem 
more  formidable 
Snarling,  growling,  scream- 
ing  (often  in  defense  of 
food) 


Cries  that  summon  aid 

Responding  to  cries  for  aid 

Flexion  of  porcupine 

Defensive  grouping  of  herd 

Attack  with  bill 

Fighting  with  wings 

Resisting  forcible  manipula- 
tion 

Struggling,  squirming,  bit- 
ing when  held 

Retaliatory  aggression 


Cleanliness 


Licking  the  body 
Dusting  plumage 
Preening 
Scratching 
Biting  parasites 
Shaking  of  wet  paw  by  kit- 
tens 


Picking   at   foreign   objects 

on  surface  of  body 
Cleaning  of  eggs  by  ants 
Rolling 
Shaking 
Scratching  dirt  over  filth 


Careful  observation  of  animals  will  disclose  the 
fact  that  practically  none  of  the  items  in  the  above 
list  refers  to  an  act  that  is  ahvays  executed  in  the 
same  way.  An  act  of  flight,  for  example,  is  never 
twice  the  same.  The  movements  depend  upon  the 
contour  of  the  ground,  upon  the  position  of  the 
enemy,  and  upon  previously  formed  habits  of  all 
sorts.    Such  "instincts"  as  these  are  nothing  more 


INSTINCT  67 

than  the  continuance  of  behavior  of  many  sorts  un- 
til a  consummatory  response  has  been  given.  A 
frightened  partridge  uses  many  means  of  escape, 
struggling,  running,  or  flying,  until  the  consumma- 
tory response  of  reaching  concealment  terminates  its 
activity. 

The  Effect  of  Vakying  Situations  upon 
Preparatory  Responses 

Greater  uniformity  in  the  order  of  the  parts  of 
an  elaborate  "instinct"  is  seen  when  each  compo- 
nent act  changes  the  situation  in  a  set  and  charac- 
teristic way.  Nest-building  is  a  case  in  point.  A 
shelf  under  the  eaves  is  a  stimulus  that  may  start 
a  mated  bird  in  its  search  for  building  materials. 
Its  return  to  this  spot  with  material  in  its  mouth 
initiates  laying  the  foundation  of  the  nest.  Its 
empty  bill  starts  it  off  again  on  a  search  for  more 
materials.  Return  is  delayed  until  its  mouth  is  again 
filled.  Its  next  nest-building  movement  is  deter- 
mined by  finding  the  nest  already  begun,  and  so  each 
step  in  the  building  is  governed  by  the  degree  of 
completion  of  the  nest  at  the  time.  This  may  be 
demonstrated  by  partially  demolishing  a  nest  which 
has  been  almost  completed.  The  bird  will  act  then 
much  as  it  did  when  the  nest  first  reached  this  stage 
of  completion. 

A  solitary  wasp  usually  leaves  her  prey  just  out- 
side the  hole,  into  which  she  goes  before  returning 


68  GENERAL  PSYCHOLOGY 

to  drag  the  food  into  the  nest.  Fabre  demonstrated 
that  if  the  food  is  removed  some  distance  from  the 
nest,  the  returning  wasp  will  again  drag  it  close  to 
the  hole,  leave  it,  and  again  enter  the  nest.  If  the 
food  is  repeatedly  moved  back,  the  wasp  will  behave 
time  and  again  in  precisely  the  same  way. 
This  nicely  illustrates  the  way  in  which  each  act  in 
the  series  is  determined  by  the  arrangement  of 
stimuli. 

Because  of  the  diversity  of  conditions  from  time 
to  time,  no  wasp  would  repeat  exactly  its  original 
movements  in  bringing  grasshoppers  to  its  hole,  and 
no  bird  would  duplicate  its  original  behavior  in 
building  a  second  nest.  The  bird's  precurrent  re- 
sponses depend  upon  the  nature  of  available  build- 
ing materials  and  the  places  where  these  materials 
are  found.  A  cat  prowling  about  the  locality  will 
greatly  alter  the  bird's  reactions,  the  sight  of  food 
may  temporarily  distract  it  from  its  building,  but 
eventually  the  nest  is  completed  after  some  com- 
bination or  another  of  precurrent  acts. 

The  wasp  observed  by  the  Peckhams  was  led  to 
one  preparatory  response  after  another  as  it  came 
by  chance  upon  the  small  objects  surrounding  the 
hole.  Although  its  tendency  to  move  small  objects 
to  the  hole  is  set  going  by  the  sight  of  the  open  hole 
and  the  presence  of  the  small  objects,  the  particular 
way  in  which  it  behaves  is  determined  by  the  nature 
and  the  position  of  these  objects.  The  sight  of  the 
stone  initiates  the  effort  to  move  it,  but  its  resist- 


INSTINCT  69 

ance  causes  the  wasp  to  relinquish  it.  It  will  then 
turn  to  any  other  material  that  may  catch  its  eye  un- 
til an  easily  moved  object  is  found,  whereupon  the 
open  hole  is  covered  and  ceases  to  exist  as  a  stimu- 
lus to  this  sort  of  behavior.  Successful  covering 
of  the  hole  is  the  consummatory  response  that  does 
away  with  the  maintaining  stimulus,  which  remained 
unabated  by  the  precurrent  responses. 

There  is  always  a  persistence  of  some  maintaining 
stimulus  if  there  is  a  persistence  of  the  consumma- 
tory response  tendency.  Courtship  is  continued 
only  as  long  as  some  internal  or  external  stimulus 
for  copulation  is  present.  Fighting  ceases  in  the 
absence  of  an  antagonist  or  when  rage  subsides. 
The  terrified  person  no  longer  flees  when  the  pur- 
suer is  distanced,  if  the  characteristic  emotional  state 
has  passed. 

Instincts,  then,  are  seen  to  be  chain  reflexes  whose 
serial  arrangement  is  determined  by  movement-pro- 
duced stimuli.  The  nervous  mechanisms  involved 
are  established  by  growth  and  are  not  the  result  of 
training.  When  the  movement-produced  stimuli  are 
external  to  the  body,  the  order  of  responses  is  more 
variable  than  when  the  stimuli  reside  in  the  body 
itself.  As  the  common  element  in  so  many  diverse 
chain  reflexes  is  the  particular  consummatory  re- 
sponse to  which  they  lead,  the  consummatory  re- 
sponse is  a  valuable  basis  for  the  classification  of 
instincts  when  a  classification  is  demanded. 


70  GENERAL  PSYCHOLOGY 

Individual  Differences 

Everyone  recognizes  the  fact  that  in  a  group  of 
horses  or  cows  or  chickens  one  individual  differs 
from  another.  Some  horses  are  naturally  faster, 
and  some  are  naturally  slower.  One  cow  is  a  good 
milker  and  another  cow  gives  but  little  milk,  even 
though  both  have  had  the  same  care  and  feeding. 
Chickens  vary  in  size  and  in  the  number  of  eggs  they 
will  lay.  Even  in  the  case  of  men  we  recognize  dif- 
ferences in  height  and  in  pigmentation  that  are  due 
to  endowment  and  not  to  education. 

It  is  a  tendency  of  our  own  times  to  be  less  willing 
to  admit  that  from  birth  one  man  differs  from  an- 
other in  intellectual  ability.  To  a  very  great  extent, 
however,  we  are  born  and  not  made.  Some  men  are 
gifted  with  brains,  and  some  are  handicapped  by  a 
natural  inferiority  for  which  no  amount  of  training 
will  compensate.  The  great  majority  of  people  in 
the  world  could  never  graduate  from  college,  because 
of  their  inadequate  intellectual  endowment. 

There  are  very  few  college  students  who  can  run 
a  hundred  yards  in  10  seconds,  more  who  can  do  it 
in  11,  still  more  who  can  do  it  in  12,  and  probably 
about  an  equal  number  who  can  do  it  in  13.  From 
this  point  on  we  find  fewer  and  fewer  students  whose 
fastest  time  is  14,  15,  16,  or  more  seconds.  If  an 
unselected  group  of  students  were  to  start  together 
to  run  the  length  of  a  football  field,  they  would  be 


INSTINCT 


71 


strung  out  at  the  finish  in  some  such  way  as  shown 
in  Figure  14. 


-sag- 


man 


/6  sec 

men 


15  sec 
men 


I      rr       iMitirT         nt|Bi      i  M—ni., 

Msec.     /J  sec.     /P  sec     //sec. 
men         men         men         men 


<%  A 


man 


FIGURE  14.     DI8TBIBUTI0N  OF  UNSELECTED  GEOUP  OF  EUNNEES 

Their  distribution  according  to  speed  might  be 
represented  graphically  as  in  Figure  15. 


6r- — — 1 1  I 1  ■■■■■■  «i  ',    ■  I 

5 

4 ___  1 

I 

3 i 

. , 


17  sec 
man 


16  sec 
men 


15  sec. 
men 


74  sec 
men 


73  sec 
men 


/2  sec. 
men 


//  sec. 

men 


/0  sec 
man 


FlGUBE    15.      SUBFACE   OF   FREQUENCY    SHOWING   THE   DISTRIBUTION   OF 

THE  BUNNEBS   OF  FIGURE   14  ACCOBDING  TO  THEIB 

TIME  IN   SECONDS 


It  is  possible  by  the  use  of  mental  tests  to  measure 
with  but  slight  error  the  amount  of  a  man's  innate 
intellectual  ability,  and  to  compare  the  amount  of 
this  natural  endowment  with  that  of  people  in  gen- 
eral. If  we  were  to  give  our  group  of  students  men- 
tal tests,  we  would  find  a  few  of  them  to  be  conspicu- 
ously bright,  more  of  them  to  be  a  little  less  intelli- 
gent, a  great  many  of  them  bunched  about  the  point 


72  GENERAL  PSYCHOLOGY 

of  average  performance,  and  fewer  and  fewer  at 
points  lower  and  lower  in  the  scale.  Such  a  meas- 
urement of  the  intelligence  of  a  number  of  groups  is 
represented  in  the  graphs  on  page  73. 

In  general,  bright  parents  have  bright  children, 
mediocre  parents  have  mediocre  children,  and  dull 
parents  have  dull  children.  Striking  exceptions  to 
this  rule  should  not  be  given  undue  weight.  The 
handicap  of  ill  health,  poverty,  or  lack  of  educational 
opportunity,  or  the  advantage  of  excellent  training 
have  some  effect  upon  the  score  that  an  individual 
makes  in  intelligence  tests.  Tests  are  designed  to 
minimize  this  effect. 

There  is  no  evidence  for  the  common  supposition 
that  the  neurological  habits  of  parents  are  passed  on 
to  their  children  in  the  form  of  instincts.  There  are, 
however,  many  experimental  results  that  suggest 
that  certain  of  the  parents'  acquired  characteristics 
are  passed  on  to  the  offspring.  All  these  trans- 
mitted bodily  modifications,  such  as  congenital  syphi- 
lis or  malnutrition,  are  of  a  sort  quite  distinct  from 
the  neurological  changes  involved  in  habit  forma- 
tion, and  offer  no  evidence  for  the  belief  that  educa- 
tion is  inherited.  Children  descended  from  genera- 
tions of  English-speaking  ancestors  are  probably  no 
quicker  in  learning  English  than  are  babies  of  for- 
eign extraction. 

It  is  not  unusual  for  people  untrained  in  biology 
to  think  they  see  contradiction  in  the  two  statements 
that  "  bright  parents  are  likely  to  have  bright  chil- 


INSTINCT 


73 


12  r 


.6  ► 


1 

.... 

, 

j 

•— , 

...- 

— 1 

, 

: 



•  tMI 



.... 

■'■"IT"' 

10     20    30    40    50    60     70    80   90    100    110    120  130  140   150  160  170    180  190  200    2  0 
Score  in  Alpha  Test 

FlGUBE    16.      DISTRIBUTION   OF  ALPHA   TEST    SCORES   FOR   COLLEGE   STU- 
DENTS  AND  FOR   THE   DRAFT   ARMY    (EQUAL   AREAS) 


40 


30 


20 


..,., 

• 

M  = 

139 

2 

-.. 

... 

... 

125 

36 

An 

<?st 

9/K 

:ers 

M  = 

58 

9 

Rlf 

20 

Nat 

ire 

rec 

WJ 

J 

de 

M  = 

38 

,6 

28 

50 

Lol 
A 

jrei 

ortn 

em 

5A 

tsti 
tes 

0,71 

M' 

-12 

.4 

17 

09 

ft?/! 

rea 

rec 

•rn 

trd 
es 

m 

,' 



1 

^5 

■»•«. 

» 

L__ 

Mai 

r«H 

— . 



-J 

1 

_.- 

-.„ 

""1 

... 

■— ' 

_ 

— 

L, 

rJ 



— 

RS 

<•••* 

iai 

»•• 

— 

— 

BM 

' 

i 

•     1 

>o  — 


20       40       60      80       100 
Score  in  Alpha  Test 


120      140       160      180     200 


Figure  17.    distribution  of  alpha  test  scores  for  various  groups 
in  the  draft  army  (equal  areas) 


74  GENERAL  PSYCHOLOGY 

dren"  and  that  "the  results  of  schooling  are  prob- 
ably not  inherited. "  This  is  because  they  suppose 
that  individual  differences  are  all  due  to  training,  a 
supposition  that  is,  of  course,  untrue. 


CHAPTER  HI 


LEARNING 


Although  all  babies  start  life  with  the  same  kinds 
of  capacities,  we  find  them  as  adults  displaying  vari- 
ous individual  abilities  that  have  been  gained  through 
practice  and  education.  They  have  become  judges, 
farmers,  carpenters,  editors,  burglars,  and  politi- 
cians. Each  has  developed  skill  along  certain  lines. 
Psychology  must  explain  how  these  diverse  habits 
are  developed. 

We  seldom  observe  in  adults  an  elaborate  act  that 
is  a  pure  instinct,  and  this  is  because  the  original 
structure  of  the  nervous  system  changes  as  a  result 
of  use.  We  must  not,  however,  fall  into  the  error 
of  supposing  that  when  any  response  is  modified  by 
learning,  it  thereupon  ceases  to  be  instinctive.  The 
instinctive  components  of  any  act  may  be  discerned, 
no  matter  how  greatly  it  has  been  transformed  by 
training. 

The  modifications  of  instinctive  behavior  that  re- 
sult from  use  are  of  two  sorts.  One  sort  of  learn- 
ing results  in  the  attachment  of  a  response  to  a  stim- 
ulus that  did  not  provoke  it  originally.  This  is  illus- 
trated by  such  a  common  act  as  reaching  for  the  tele- 
phone receiver  when  the  bell  rings.     A  baby  or  a 

75 


76  GENERAL  PSYCHOLOGY 

savage  does  not  respond  in  such  a  way  to  this  stimu- 
lus. Another  sort  of  learning  is  a  modification  of 
the  ease  with  which  a  response  may  be  elicited.  Un- 
der certain  conditions  a  person  may  develop  a  ready 
anger  toward  interruptions  when  at  work,  and  un- 
der other  conditions  he  may  develop  toward  the  same 
occurrences  an  increasing  toleration. 

All  habits,  no  matter  how  complex,  are  the  results 
of  these  easily  understood  changes  in  stimulus-re- 
sponse mechanisms.  We  shall  first  consider  the 
modifications  in  the  ease  with  which  responses  are 
brought  about,  and  later,  under  the  heading  "The 
Conditioned  Response,"  we  shall  discuss  the  at- 
tachment of  responses  to  new  stimuli. 

Positive  Adaptation 

Repeated  working  of  a  stimulus-response  mechan- 
ism, especially  if  the  stimulus  is  just  above  the 
threshold  of  response,  results  in  lowering  the  thresh- 
old, in  decreasing  the  reaction  time,  and  in  increas- 
ing the  vigor  with  which  the  response  is  given.  This 
effect  of  repeated  working  is  called  positive  adapta- 
tion. 

Because  of  practice,  the  lookout  on  board  ship  is 
able  to  signal  the  approach  of  a  vessel  more  readily 
than  is  the  landsman  who  stands  beside  him.  If  the 
situation  is  such  that  we  always  get  up  when  the 
alarm  clock  rings,  the  clock  may  be  moved  farther 
and  farther  from  the  bed  on  successive  nights,  un- 


LEARNING  77 

til  we  are  finally  aroused  by  a  sound  much  too  faint 
to  have  gotten  us  out  of  bed  on  the  first  morning.  A 
physician  may  develop  a  positive  adaptation  to  the 
telephone  at  night,  while  his  wife  sleeps  through  the 
disturbance.  His  wife,  on  the  other  hand,  is  often 
the  one  who  responds  to  the  crying  of  the  baby.  The 
suburbanite  develops  a  sensitive  ear  to  the  whistle 
of  the  early  train ;  the  bank  teller  is  quick  to  detect 
counterfeit  money ;  the  woodsman  notices  signs  that 
escape  the  city  dweller;  and  all  of  us  turn  when  a 
dime  is  dropped  even  on  a  noisy  street.  If  we  were 
to  see  two  signboards  side  by  side  and  lettered  in 
the  same  type,  one  bearing  the  words  BULL 
DURHAM  and  the  other  the  nonsense  words  RAHD 
LULBUM,  and  if  these  were  just  near  enough  to 
enable  us  to  read  the  first  of  these  signs,  we  would 
not  be  able  to  decipher  the  second,  though  the  same 
letters  occur  on  the  two  signs.  We  do  not  develop 
positive  adaptation  to  all  stimuli  that  act  upon  sense 
organs,  but  only  to  those  that  provoke  a  response. 

When  we  first  learn  to  perform  an  act  in  response 
to  a  new  stimulus,  the  time  involved  in  giving  the 
response  is  much  longer  than  it  is  at  a  later  period, 
after  practice.  This  shortening  of  reaction  time  is 
best  studied  where  a  large  number  of  stimuli  are 
responded  to  in  novel  ways,  as  in  learning  to  type- 
write, to  send  or  receive  telegraphic  messages,  to 
translate  a  foreign  text,  or  to  take  dictation  in  short- 
hand. By  measuring  the  performance  of  any  of 
these  acts  during  successive  practice  periods,  and 


78 


GENERAL  PSYCHOLOGY 


by  plotting  these  measurements,  we  get  what  is 
called  a  practice  curve.  An  illustration  is  given  in 
Figure  18. 

In  telegraphy  the  practice  curve  for  either  send- 
ing or  receiving  shows  that  more  and  more  words 


FlGUBE  18.  CURVE  OF  PRACTICE  IN  MIRROR  DRAWING.  EACH  ORDINATE 
REPRESENTS  THE  AVERAGE  TIME  OF  50  SUBJECTS.  THE  FUNCTION 
PRACTISED  WAS  DRAWING  A  CIRCLE  BETWEEN  THE  DOUBLE  LINES.  THE 
FIGUBE  WAS  SCBEENED  FROM  THE  SUBJECTS  AND  VISIBLE  ONLY  IN  A 
MIRROR.  THE  OUTER  CIRCLE  WAS  FOUR  INCHES  IN  DIAMETER.  THE 
TRACK  BETWEEN  THE  TWO  CIRCLES  WAS  AN  EIGHTH 
OF  AN    INCH    WIDE 


may  be  handled  in  a  given  time  as  practice  continues. 
There  is,  of  course,  a  limit  to  such  improvement,  and 
the  telegrapher  finally  approximates  his  maximum 
speed.    As  this  limit  is  approached  the  curve  flat- 


LEARNING  79 

tens  out.     Thus  the  first  part  of  practice  is  rela- 
tively more  fruitful  than  the  last  part.1 

Through  use,  the  tendency  of  a  response  to  follow 
its  stimulus  becomes  better  established.  This 
greater  tendency  to  sequence  is  shown  not  only  in 
a  lowered  threshold  and  a  shortened  reaction  time, 
but  in  an  increased  resistance  to  distraction.  The 
practised  act  is  performed  in  the  face  of  altered  con- 
ditions and  in  spite  of  internal  variations  that  would 
have  prevented  the  reaction  originally. 

Positive  adaptation  is  gradually  lost  after  prac- 
tice has  been  discontinued.  This  slow  disappear- 
ance of  positive  adaptation  is  called  forgetting,  and 
may  be  measured  just  as  the  appearance  of  posi- 
tive adaptation  may  be  measured.  The  rate  of  for- 
getting, as  graphically  represented,  is  at  first  rapid. 
(See  Figure  25.)  As  time  passes,  the  loss  of  prac- 
tice effects  takes  place  at  a  slower  rate,  and  even 
after  years  of  disuse,  a  stimulus-response  mechanism 
may  still  show  traces  of  positive  adaptation.  Horse 
buyers  determine  whether  a  horse  has  ever  had 
mange  by  stroking  the  horse's  flank.  A  horse  that 
has  had  mange,  and  has  through  practice  developed 
positive  adaptation  of  the  natural  skin-biting  re- 
sponse, will  respond  years  later  by  a  quivering  of 
the  lip. 

i  Thorndike,  "Notes  on  Practice,  Improvability,  and  the  Curve  of 
Work,"  American  Journal  Psychology,  1916,  pp.  550-565.  Hill,  Re- 
jall,  and  Thorndike,  "Practice  in  the  Case  of  Typewriting,"  Ped- 
agogical Seminar,  1913,  pp.  516-529.  Lashley,  "The  Acquisition  of 
Skill  in  Archery,"  Carnegie  Institute,  1915. 


80  GENERAL  PSYCHOLOGY 

Anyone  who  has  narrowly  escaped  being  struck  by 
lightning  shows  a  greater  i'ear  response  than  before 
to  the  distant  thunder  storm.  If  we  have  been  pro- 
voked to  anger  by  another's  outrageous  act,  he  may 
arouse  our  anger  again  by  the  most  trivial  discour- 
tesy. At  tirst  this  might  seem  to  be  evidence  that 
positive  adapt  alien  results  best  from  responses  to 
intense  stimuli  but  this  is  probably  not  so. 

It  requires  a  very  intense  stimulus  to  call  out  an 
extensive,  diffuse,  and  complete  emotional  response, 
although  parts  of  the  response  may  be  given  to  a 
weak  stimulus.  Once  the  response  has  been  called 
out  in  its  entirety,  the  elements  originally  having 
high  thresholds  are  more  easily  elicited  and  the  act 
as  a  whole  is  bound  together  by  what  we  shall  later 
call  conditioning.  This  explains  why  a  child  who 
has  been  thoroughly  frightened  shows  cowardice  ou 
slight  provocation.  His  entire  fear  mechanism  has 
been  called  into  action,  and  the  partial  fear  response, 
which  is  ordinarily  given  by  children  who  have  never 
known  abject  fear,  gives  place  to  a  more  complete 
expression  upon  insignificant  occasion.  The  child 
who  has  often  hem  teased  to  a  point  of  rage,  shows 
positive  adaptation  o(  those  parts  of  the  rage  re- 
sponse that  are  naturally  more  difficult  to  elicit,  and 
thus  develops  a  bad  temper  toward  small  grievances. 

Negative  Adaptation 

If  a  subliminal  stimulus  is  repeated  with  gradu- 
ally increasing  intensity,  the  response  may  not  0C- 


LEARNING  81 

cur  when  the  stimulus  reaches  or  even  passes  the 
usual  threshold  point,  and  in  this  way,  especially  if 
the  response  is  never  given,  the  threshold  of  re- 
sponse will  be  raised.  This  is  called  negative  adap- 
tation. 

If  the  temperature  of  the  room  falls  gradually, 
we  fail  to  notice  it,  but  if,  for  any  reason,  it  suddenly 
becomes  cold,  we  react  to  the  change.    If  the  cost 
of  living  were  to  double  over-night,  there  would  be 
public  disorder  the  next  day,  but,  because  the  dou- 
bling is  a  gradual  process  occupying  several  years, 
the  situation  remains  below  the  threshold  for  rioting. 
The  physician  is  inured  to  the  suffering  of  others 
by  witnessing  it  repeatedly,  and  by  the  necessary 
inhibition  of  any  useless  expression  of  sympathy. 
A  child  who  is  afraid  to  sleep  without  a  light  may 
become  adapted  to  sleeping  in  entire  darkness  by  a 
gradual  reduction  of  the  intensity  of  the  light  on 
successive  nights.    The  practised  person  while  using 
a  microscope,  shows  negative  adaptation  for  stimuli 
affecting  his  left  eye.     The  disobedient  child  is  in- 
different to  his  parent's  call  because  he  has  failed, 
on  many  occasions,  to  respond.    In  order  to  train  a 
dog  to  come  when  called,  the  expert  dog  trainer 
never  uses  the  dog's  name  except  in  summoning  him. 
The  visitor  in  a  household  is  disturbed  by  the  chil- 
dren's noise,  while  the  parents  may  have  become 
adapted  to  it.    Many  parents  also  become  negatively 
adapted  to  their  children's  questions  and  are  sur- 
prised when  their  attention  is  called  to  this. 


82  GENERAL  PSYCHOLOGY 

James  thought  it  unfortunate  that  man  is  en- 
dowed with  a  fear  response,  the  severity  of  which 
often  renders  him  helpless  in  the  face  of  danger.2 
Nearly  anyone,  if  he  were  compelled  to  walk  an 
I-beam  high  above  the  street,  would  be  seized  by 
panic  and  would  fall.  But  James  overlooked  the  fact 
that  this  original  over-supply  of  fear  is  of  value 
when  it  is  ultimately  decreased  by  negative  adapta- 
tion to  the  dangerous  situation.  If  fear  were  not 
found  in  excess  in  the  ingenuous  man,  the  danger- 
adapted  man  would  often  die  of  foolhardiness.  Ex- 
cessive embarrassment  handicaps  the  adolescent  in 
the  presence  of  strangers,  but  we  all  dislike  the  adult 
in  whom  negative  adaptation  has  been  so  thorough- 
going as  to  leave  no  traces  of  reticence. 

A  man  is  saved  from  feeling  distaste  for  his  age- 
ing wife  because  wives  grow  old  gradually,  and  he 
becomes  negatively  adapted  to  characteristics  that, 
were  they  to  occur  suddenly,  would  discourage  his 
affection.  The  proper  way  to  break  a  horse  to  the 
saddle  is  to  accustom  him  first  to  a  blanket,  next 
to  blanket  and  surcingle,  then  to  the  saddle  in  addi- 
tion. Later,  to  adapt  him  to  the  pressure  of  the 
rider,  a  bag  of  feed  of  gradually  increased  weight 
may  be  strapped  across  the  saddle.  Successful 
breaking  depends  upon  keeping  the  stimuli  within 
the  horse's  growing  toleration.  A  disliked  food 
taken  in  quantities  sufficiently  small  to  excite  no 
disgust,    may    be    eaten    in    gradually    increasing 

2  James,  Principles  of  Psychology,  vol.  ii.,  p.  419. 


LEARNING  83 

amounts  on  successive  occasions  until  a  large  portion 
does  not  cause  aversion.  Crowding  the  threshold 
for  intolerance  of  a  stimulus,  without  reaching  the 
breaking  point,  makes  for  increased  tolerance. 

Another  way  in  which  negative  adaptation  may- 
result  is  by  the  failure  of  the  response,  though  given, 
to  rid  the  animal  of  the  stimulus.  In  such  a  case, 
the  stimulus-response  mechanism  becomes  fatigued, 
and  the  response  is  given  less  and  less  energetically 
to  the  persistent  stimulus,  until  all  response  ceases. 
The  horse  that  is  broken  by  the  cow-puncher  method 
becomes  accustomed  to  the  saddle  when  his  efforts 
to  dislodge  it  repeatedly  fail,  and  so,  while  he  may 
always  make  slight  movements  of  resistance  while 
being  saddled,  the  threshold  of  resistance  is  perma- 
nently raised. 

We  have  said  that  negative  adaptation  may  be 
brought  about  in  two  ways.  The  repetition  of  a  sub- 
liminal stimulus  may  cause  it ;  or  it  may  result  when 
a  stimulus  persists  in  spite  of  the  animal's  respon- 
ses, after  fatigue  has  raised  the  threshold.  There  is 
a  third  kind  of  situation  that  results  in  negative 
adaptation.  An  eliciting  stimulus  may  be  rendered 
ineffective  by  the  presence  of  an  inhibiting  stimulus, 
and,  the  threshold  of  response  being  thus  raised, 
negative  adaptation  results.  In  this  way  children  be- 
come negatively  adapted  to  temptingly  accessible 
food  by  the  inhibiting  threat  of  punishment.  In 
Triplett's  experiments,  perch  were  separated  from 
minnows,  which  are  their  natural  food,  by  a  glass 


84  GENERAL  PSYCHOLOGY 

partition  in  the  aquarium.  A  perch  would  at  first 
dart  toward  a  minnow,  but  would  strike  its  head 
against  the  glass.  In  time  the  big  fish  became  nega- 
tively adapted  to  the  presence  of  the  minnows.  The 
partition  was  then  removed  and  the  minnows  mixed 
safely  with  their  natural  enemies.  This  case,  though 
an  example  of  negative  adaptation,  involves  a  con- 
ditioned response,  and  this  will  be  discussed  below.3 
Both  negative  adaptation  and  summation  follow 
upon  the  repetition  of  subliminal  stimuli,  though 
they  are  quite  different  results  of  such  repetition. 
It  is  the  length  of  the  intervals  between  the  stimuli 
that  determines  which  one  of  these  two  effects  will 
occur.  A  series  that  will  have  a  summation  effect, 
and  finally  bring  about  a  response,  may  lose  that 
effect  if  the  length  of  the  intervals  between  stimuli 
is  increased,  in  which  case  negative  adaptation,  or 
the  permanent  raising  of  the  threshold,  takes  place. 
These  alternative  possibilities  are  seen  not  only  in 
behavior  but  in  the  physiological  responses  of  the 
body  to  drugs.  If  one  dose  rapidly  follows  another, 
a  cumulative  effect  results,  but  if  gradually  increas- 
ing doses  are  given  at  widely  separated  intervals, 
negative  adaptation  results,  so  that  the  patient  may 
come  to  tolerate  amounts  of  the  drug  that  would 
have  been  fatal  at  the  outset. 

3  Triplett,  "The  Educability  of  the  Perch,"  American  Journal  of 
Psychology,  vol.  12,  p.  354. 


LEARNING  85 

Transitory  Changes  of  Threshold  During  a  Single 
Practice  Period 

If  a  considerable  time  has  passed  since  an  act  was 
last  performed,  the  threshold  of  response  is  found 
to  be  unusually  high  and  the  reaction  time  to  be  un- 
usually long.  When  a  ball  player  begins  his  day's 
practice,  he  is  less  sensitive  to  situations  and  slower 
to  respond  than  he  is  after  fifteen  minutes  of  warm- 
ing up.  In  golf  we  take  a  few  practice  strokes  be- 
fore driving  from  the  first  tee  in  order  to  pass  this 
period  of  sluggish  reaction.  The  slowness  and  the 
weakness  of  response  and  the  high  threshold  that 
characterize  the  beginning  of  any  activity  we  shall 
call  initial  torpor.* 

Initial  torpor  is  seen  in  simplest  form  in  the  con- 
tractility of  the  muscle-nerve  preparation  or  in  a 
spinal  reflex.  When  it  is  exhibited  in  such  a  com- 
plex act  as  game  playing  or  factory  work,  other  ele- 
ments enter  in  to  make  it  appear  greater  than  it 
really  is.  When  work  has  first  begun,  negative 
adaptation  to  distraction  has  not  yet  occurred. 
Passers-by,  noises,  and  room  temperature,  all  dis- 
turb us  at  first,  but  later,  through  negative  adapta- 
tion, are  disregarded. 

Another  obscuring  factor  is  the  hangover  of  re- 
sponses recently  given.  Conversation  just  engaged 
in  leaves  the  talker  for  some  time  afterward  still 

*  Thorndike,  Educational  Psychology,  vol.  ii. 


86  GENERAL  PSYCHOLOGY 

talking  to  himself.  If  we  turn  from  chess  to  letter 
writing,  a  tendency  to  make  chess  moves  hampers 
the  composition  of  our  first  paragraph.  The  student 
who  has  hurried  to  avoid  being  late  at  class  is  agi- 
tated for  some  time  after  taking  his  seat.  This  hang- 
over of  recent  movements  is  due  partly  to  the  per- 
sistence of  emotional  reenforcement. 

A  complex  habit  is  made  up  of  many  parts  and  in- 
volves many  action  systems.  Initial  torpor  attaches 
to  each  part  and  to  each  emotional  reenforcement. 
It  is  dissipated  in  the  parts  of  lowest  threshold  be- 
fore it  disappears  in  others.  As  one  part  after 
another  of  the  entire  act  is  brought  into  play  by  ten- 
tative beginnings,  and  by  the  stimuli  that  these  be- 
ginnings bring  to  bear  upon  us,  the  several  parts  of 
the  act  successively  lose  their  sluggishness  and  com- 
bine into  the  act  as  a  whole.  After  such  warming  up 
the  entire  habit  has  a  lowered  threshold. 

Every  time  work  is  begun  after  a  long  period  of 
rest,  initial  torpor  is  found  to  be  present.  If  the 
practice  curve  is  still  rising  and  has  not  reached  a 
plateau,  the  absolute  amount  of  initial  torpor  to  be 
overcome  is  less  at  the  beginning  of  each  successive 
practice  period.  There  is  no  difference  in  kind  be- 
tween the  positive  adaptation  shown  in  overcoming 
initial  torpor  and  the  positive  adaptation  that  is  the 
gradually  decreased  reaction  time  and  lowered 
threshold  of  an  act  practised  at  intervals  for  many 
days  and  graphically  represented  by  the  practice 
curve  as  a  whole. 


LEARNING  87 

Toward  the  end  of  the  doubleheader  the  ball 
player  again  becomes  less  sensitive  to  situations  and 
slower  in  response,  and  this  we  call  fatigue.  Toward 
the  end  of  the  shift  in  the  factory  the  number  of  ao- 


4            H 

t     l 

■ 

*     X 

4-          3 

~? 

°>               Z        J 

2  "^ -*«  ?* 

E              -t         A 

> 

%         2 

i          -j 

%        j 

i-        Z 

k       t 

t      _^ 

*T    ..,.    _J 

I      /- 

\              i 

_t     >^~ 

%     t 

jf 

^ 

S 

is 

Ql 

ki 

5 

6       7       8       3 

O'CLOCK 


10       11      12       1 


Figure     19.      distribution     of    germ  an    industrial    accidents 

throughout  the  working  day,  in  part  the  result 

of  fatigue  (after  goldmark) 

cidents  increases.5  The  third  time  around  the  links 
we  make  a  poor  score.  Fatigue  is  the  slowness  of 
response,  the  weakness  of  response,  and  the  high 

6  Goldmark,   "Fatigue  and   Efficiency,"   Russell   Sage  Foundation, 
1912,  p.  71. 


88  GENERAL  PSYCHOLOGY 

threshold  of  response  that  finally  occur  if  any  activ- 
ity is  continued  long  and  vigorously.  It  is  a  tempo- 
rary effect  of  repeated  action,  and  a  period  of  rest 
causes  it  to  vanish.6 

Variations  in  response  threshold  may  result  either 
from  variations  in  the  conductivity  of  synapses,  or 
from  variations  in  the  contractility  of  muscles.  The 
high  threshold  that  characterizes  initial  torpor  seems 
mainly  the  result  of  resistance  at  synapses,  a  condi- 
tion that  is  reduced  by  practice.  The  high  response 
threshold  in  fatigue  is  the  result  chiefly  of  a  reduced 
contractility  in  the  muscle,  which  is  brought  about 
by  exercise. 

The  Conditioned  Response 

How  may  a  response  be  provoked  by  a  new  stimu- 
lus? Let  us  take  the  case  of  a  dog  that  sees  a  cat. 
On  seeing  the  cat  he  barks.  Suppose  that  while 
looking  at  the  cat  he  hears  his  master  say  the  word 
"cats",  and  that  these  two  stimuli  occur  together 
several  times.  Later  if  he  hears  the  word  "cats", 
although  there  is  no  cat  present,  he  will  bark.  This 
response  first  called  forth  by  the  sight  of  a  cat  is 
now  provoked  by  a  new  stimulus,  namely,  the  sound 
of  a  word.  When  a  response  is  elicited  by  a  new 
stimulus,  because  of  the  fact  that  the  new  stimulus 
has  occurred  along  with  the  old,  it  is  called  a  condi- 
tioned response. 

c  Thorndike,  "Fatigue  in  a  Complex  Function,"  Psychological  Re- 
view, 1914,  pp.  402-407. 


LEARNING  89 

If  a  percussion  hammer  falls  upon  the  patellar 
tendon,  a  spinal  reflex  is  elicited  involving  the  con- 
traction of  the  quadriceps  muscle.  This  is  called  the 
knee-jerk.  In  1902,  Twitmyer  demonstrated  that  if 
a  bell  was  sounded  each  time  that  a  hammer  fell  on 
the  patellar  tendon,  it  was  possible,  after  consider- 
able practice  had  occurred,  to  elicit  the  knee-jerk  by 
the  auditory  stimulus  alone.7  To-day  a  reflex  re- 
sponse to  a  substituted  stimulus  is  called  a  condi- 
tioned reflex,  because  the  substituted  stimulus  is  one 
of  the  conditions  accompanying  the  original  stimu- 
lus. Pavlow  discovered  that  a  conditioned  salivary 
reflex  could  be  secured  from  dogs.  Certain  foods, 
when  eaten,  cause  a  copious  secretion  of  the  salivary 
glands.  He  found  that,  if  some  visual  or  auditory 
stimulus  is  made  the  invariable  accompaniment  of 
the  saliva-exciting  food,  the  accompanying  condition 
will  provoke  the  salivary  flow  in  the  absence  of  the 
original  food  stimulus.  Watson  and  Lashley  dem- 
onstrated the  conditioned  salivary  reflex  in  man  as 
well  as  other  conditioned  reflexes  in  both  dogs  and 
human  beings.8 

The  principle  that  one  of  the  accompanying  condi- 
tions of  a  stimulus  responded  to  may  later  become  a 
substituted  stimulus  for  the  response,  applies  to  all 
associative  learning.  If  a  bell  is  attached  to  a  dog's 
tail  and  the  dog  is  petted  in  a  way  to  make  him  wag 
his  tail,  the  sound  of  the  bell  will  be  an  ever  present 

t  Twitmyer,  "A  Study  of  the  Knee-jerk,"  Philadelphia,  1902. 
8  Watson,  Psychology  from  the  Standpoint  of  a  Behaviorist,  pp. 
29-38. 


90  GENERAL  PSYCHOLOGY 

condition  under  which  the  caudal  response  is  elicited. 
After  considerable  wagging  of  the  belled  tail  the  bell 
may  be  removed  and  the  wagging  produced  without 
petting  when  the  dog  hears  the  bell  rung.  In  order 
to  make  a  dog  respond  to  his  name  when  called,  the 
trainer  secures  this  response  first  to  food  and  then, 
while  the  dog  is  coming,  speaks  his  name.  In  time 
the  sound  of  the  name  becomes  the  substituted  stimu- 
lus for  approach. 

If  a  number  of  photographs  is  presented  to  a  sub- 
ject each  one  being  named  by  the  experimenter  and 
then  by  the  subject  as  he  looks  at  the  photograph, 
a  conditioned  response  will  be  established  in  time 
toward  each  picture,  so  that  the  subject  will  call  it 
by  the  proper  name.  The  previous  stimulus  for  this 
response  was  the  word  spoken  by  the  experimenter, 
and  the  substituted  stimulus  is  the  accompanying 
visual  representation.  In  like  manner  probably  any 
response  may  be  conditioned  by  accompanying  stim- 
uli in  the  absence  of  the  original  stimulus.  Nausea 
may  occur  at  the  mere  sight  or  odor  of  food  in  which 
a  nauseating  medicine  was  once  taken  or  that  was 
eaten  during  a  storm  at  sea.  This  fact  was  made 
use  of  in  curing  the  whiskey  habit.  Mark  Twain 
found  it  difficult  to  speak  on  serious  matters  in  public 
because  he  himself  constituted  a  conditioning  stimu- 
lus that  always  provoked  laughter  in  his  audience.9 


•  Interesting  examples  of  conditioned  emotional  responses  are  de- 
scribed by  Locke  in  his  Essay  Concerning  Human  Understanding, 
Book  2,  Chapter  33. 


LEARNING  91 

Conditioned  Emotional  Responses 

An  interesting  example  of  a  conditioned  response 
is  seen  in  the  attachment  of  an  emotional  expression 
to  some  situation  that  originally  had  no  power  to 
bring  out  the  emotion.  Probably  each  emotion  is 
originally  provoked  by  a  very  limited  number  of  sit- 
uations. Tickling  is  the  adequate  stimulus  for  caus- 
ing the  baby  to  smile,  but  the  baby  may  learn  to 
smile  at  sight  of  the  person  who  has  tickled  him  be- 
cause he  has  been  exposed  simultaneously  to  the 
tickling  and  to  the  sight  of  the  tickler.  He  is  not 
originally  afraid  of  the  sight  of  a  dog  and  indeed 
will  ordinarily  reach  toward  it,  but  once  frightened 
by  its  bark  or  knocked  down  by  its  rush  the  subse- 
quent sight  of  the  dog  is  sufficient  to  cause  the  ex- 
pression of  fear.10  The  dog  once  kicked  by  the  milk- 
man will  fly  into  a  rage  at  sight  of  him,  his  rage  re- 
sponse being  originally  provoked  by  the  kick,  but 
conditioned  by  the  appearance  of  the  man. 

It  is  in  this  way  that  we  learn  to  show  anger,  joy, 
fear,  love,  disgust,  and  other  emotions  in  response  to 
those  occurrences  of  life  that  are  apt  to  be  followed 
by  events  that  make  these  responses  appropriate. 
Thus  we  anticipate  the  attack  of  a  familiar  foe,  or 
by  an  early  withdrawal  avoid  too  close  proximity  to 
the  frightful  object.     Many  of  our  fears,  likes,  or 

10  An  experiment  in  establishing  conditioned  emotional  responses 
in  an  infant  i8  described  by  Watson  and  Rayner,  "Conditioned  Emo- 
tional Reactions/'  Journal  of  Experimental  Psychology,  1920,  pp. 
1-14. 


92  GENERAL  PSYCHOLOGY 

dislikes  are  conditioned  responses  to  stimuli  that 
have  only  a  chance  temporal  connection  with  their 
natural  provocation.  A  celluloid  collar  in  itself  is 
neither  alluring  nor  repulsive,  and  our  dislike  of 
such  an  article  of  dress  is  dependent  upon  the  fact 
that  we  have  always  experienced  it  in  connection 
with  a  wearer  who  is  not  too  scrupulous  as  to  his 
personal  cleanliness.  Everyone  builds  up  a  set  of 
emotional  tendencies  through  this  process  of  associa- 
tion, so  that  his  adult  attitude  toward  the  experien- 
ces of  life  is  fitted  to  the  culture  into  which  he  has 
been  born. 

Particular  .melodies  become  associated  with  the 
WT>rds  of  songs  and  with  emotional  expressions  that 
have  been  called  out  by  these  words.  Although  at 
first  only  the  words  may  have  had  the  power  to 
arouse  the  emotions  in  question,  the  music  itself,  in 
the  absence  of  the  words,  will  later  have  the  same 
effect.  Easter  and  Christmas  music,  the  melody 
to  which  sentimental  words  were  sung,  patriotic 
airs,  the  words  of  which  originally  excited  patriotic 
emotions,  or  the  music  sung  at  the  funeral  of 
a  friend,  will  long  afterward  revive  the  emotional 
expression  of  which  they  were  at  first  the  incidental 
accompaniment.  Conversely,  music  itself  may  di- 
rectly arouse  emotional  responses,  and  this  fact  is 
made  use  of  to  reenforce  the  conviction  that  the  at- 
tending words  but  partly  establish.  The  stirring 
airs  of  the  camp  meeting  or  the  patriotic  rally  bring 
many  to  the  mourner's  bench  or  the  recruiting  office 


LEARNING  93 

who  would  remain  sinners  or  slackers  if  appealed  to 
by  words  alone. 

Emotional  expressions  as  a  whole  may  be  attached 
to  new  stimuli,  and  in  inappropriate  situations  con- 
stitute many  of  the  psychoneuroses.  If  in  the  pro- 
cess of  courtship  a  person  is  placed  in  a  position  to 
arouse  great  fear,  the  emotion  of  fear  may  become 
attached  to  all  erotic  stimuli,  and  what  is  known  as 
an  anxiety  neurosis  may  develop.  Cases  have  been 
reported  in  which  an  aversion  for  small  rooms  can  be 
attributed  to  the  subject's  having  fainted  at  one  time 
in  a  small  close  room ;  in  which  a  fear  of  buzzing  in- 
sects followed  a  child's  being  frightened  by  a  hum- 
ming bird  that  entered  a  window  and  flew  rapidly 
about  the  child's  head;*  in  which  a  horror  of  bells 
was  caused  by  a  church  bell's  ringing  at  a  time  when 
great  depression,  resulting  from  her  mother's  death, 
possessed  the  subject,  who  believed  herself  responsi- 
ble for  her  mother's  illness.  Such  conditions  often 
call  for  treatment  at  the  hands  of  a  psychologist.11 

The  way  in  which  these  bad  habits  of  emotional  re- 
sponse are  cured  is  to  attach  a  rival  response  to  the 
stimulus  that  arouses  them.  If,  for  example,  a  per- 
son shows  a  morbid  aversion  towards  touching  ab- 
sorbent cotton,  the  psychoanalyst  attempts  to  dis- 
cover the  origin  of  this  response  by  delving  into  the 
subject's  past.  It  may  be  found  that  as  a.  child  the 
subject  once  handled  some  dirty  cotton  that  had  been 

11  Hollingworth,  The  Psychology  of  Functional  Neuroses,  New  York, 
1920. 


94  GENERAL  PSYCHOLOGY 

used  as  a  surgical  dressing,  and  that  he  was  at  that 
time  scolded  by  a  disgusted  parent.  For  practical 
purposes  it  probably  does  not  matter  whether  this 
event  was  the  occasion  of  the  subject's  original  dis- 
taste for  cotton,  provided  the  subject  himself  is  con- 
vinced that  this  was  the  real  cause.  With  this  start, 
the  psychoanalyst  proceeds  to  lower  the  threshold 
for  the  recollection  of  this  childhood  event,  and  so 
makes  certain  that  the  subject  will  always  think  of 
the  event  when  cotton  is  seen.  The  subject  is  then 
told  that  little  children  can  not  be  held  responsible 
for  failure  to  avoid  unsanitary  acts,  that  the  sub- 
ject himself  was  in  no  way  to  be  blamed  for  what 
he  did,  that  certainly  no  harm  resulted  from  his  act, 
and  that,  indeed,  the  whole  matter  is  very  ludicrous 
as  we  look  back  upon  it. 

In  this  way  there  becomes  attached  to  the  sight  of 
cotton  the  tendency  to  discuss  the  childhood  event 
and  for  such  discussion  to  be  accompanied  by  self- 
satisfaction  and  amusement.  If  this  line  of  response 
is  sufficiently  practised  and  sufficiently  reenforced 
by  verbal  rationalization,  it  develops  a  threshold 
that  is  lower  than  that  of  the  aversion  response, 
and  thus  the  aversion  habit  is  cured. 

The  Substitution  of  Similar  Stimuli 

An  act  may  be  learned  in  response  to  one  situation 
and  later  given  to  another  that  is  partially  identical, 
even  though  the  common  elements  in  the  two  situa- 


LEARNING  95 

tions  are  wholly  incidental  and  irrelevant.  This 
substitution  does  not  involve  the  process  of  condi- 
tioning. It  is  nicely  illustrated  by  many  false  moves 
in  everyday  life.  The  following  cases  have  been  ob- 
served recently.  A  person  was  about  to  make  tea. 
Instead  of  turning  on  the  gas  for  the  Bunsen  burner, 
lighting  it  with  a  match,  turning  on  the  water  faucet, 
filling  the  kettle,  and  placing  the  kettle  over  the 
burner,  he  made  the  mistake  of  turning  on  the  water, 
lighting  the  match,  and  placing  the  match  under  the 
faucet.  The  mistake,  of  course,  was  due  to  the  sim- 
ilarity of  proprioceptive  stimulation  involved  in 
turning  the  gas  cock  and  opening  the  water  faucet, 
the  false  response  being  practically  the  same  as  the 
gas-lighting  response.  Another  example  of  the  sub- 
stitution of  one  stimulus  for  another,  because  of 
partial  identity,  was  found  in  the  case  of  a  man  who 
entered  a  shop  to  purchase  a  newspaper  and  who 
dropped  his  money  on  the  floor.  He  picked  up  the 
money  and  left  the  shop  without  securing  the  paper, 
and  did  not  appreciate  his  mistake  until  he  was  some 
distance  away.  Here  the  responses  of  picking  up  the 
coin  and  of  picking  up  the  newspaper  are  almost 
identical,  and  the  mere  act  of  picking  something  up 
was  the  usual  stimulus  for  leaving  the  shop. 

Facilitating  Effect  of  Conditioning  Stimuli 

If  a  dog  that  has  been  trained  to  respond  to  the 
word  "cats"  sees  a  cat  at  such  a  distance  that  the 


96  GENERAL  PSYCHOLOGY 

stimulus  is  below  the  threshold  for  chasing,  his  mas- 
ter may  urge  him  on  by  using  the  word  and  he  may 
at  once  start  in  pursuit.  In  this  way  the  sound  of 
the  word  "cats",  although  not  now  the  sole  cause 
of  the  response,  facilitates  the  response,  because  it 
occurs  in  conjunction  with  the  actuating  stimulus. 

Illustrations  of  these  conditioning  stimuli  and 
their  resulting  facilitation  are  plentiful  in  everyday 
life.  The  literary  man  accustomed  to  writing  while 
smoking  a  pipe  finds  it  difficult  to  work  without  the 
pipe  in  his  mouth.  The  clergyman  is  moved  to 
greater  eloquence  when  wearing  his  cassock,  and 
would  find  it  difficult  to  preach  a  sermon  on  the 
street  corner.  The  college  instructor,  because  he 
frequently  uses  chalk  during  lectures,  finds  facilita- 
tion to  his  speech  through  holding  a  piece  of  chalk  in 
his  hand.  Our  familiar  surroundings  increase  our 
personal  efficiency,  and  this  law  gives  a  psychological 
justification  to  the  so-called  right  of  personal  prop- 
erty. 

A  man  sleeps  best  in  his  own  bed,  not  only  because 
he  is  negatively  adapted  to  the  distracting  stimuli 
of  his  neighborhood,  but  because  he  has  gone  to  sleep 
many  times  in  these  surroundings  and  they  have  a 
facilitating  effect  in  producing  slumber.  A  child 
often  refuses  to  sleep  unless  covered  by  a  familiar 
blanket,  or  allowed  to  suck  his  thumb,  or  permitted 
to  take  a  certain  doll  to  bed  with  him. 


LEARNING  97 

Neural  Basis  of  Learning 

Conditioned  responses  involve  the  formation  of 
new  pathways  and  the  possibility  for  this  is  best 
afforded  by  the  intricate  association  fibres  of  the 
cortex.  When  a  neural  arc  is  acting,  impulses  re- 
ceived from  sense  organs  not  previously  connected 
with  this  neural  arc  are  likely  to  be  drained  into  its 
outgoing  motor  pathway.  This  drainage  establishes 
new  synapses  and  thus  connects  new  sense  organs 
with  the  responding  muscle  or  gland.  This  is  the 
neural  basis  of  the  conditioned  response.  It  may  be 
best  understood  by  consulting  the  diagram  in  Fig- 
ure 20. 

Impulses  aroused  by  accompanying  conditioning 
stimuli  are  drained  into  the  motor  system  that  is 
active  at  the  time.  Thus  when  the  original  stimulus 
and  the  conditioning  stimulus  act  together,  the  com- 
bined energy  from  the  two  is  drained  into  a  single 
motor  system.  For  this  reason  the  conditioning 
stimulus  facilitates  the  action  of  the  original  me- 
chanism and  this  mechanism  may  act  with  a  stimu- 
lation less  intense  than  was  first  required. 

The  changes  in  the  nervous  system  that  account 
for  positive  adaptation  are  presumably  an  increase 
in  conductivity  at  synapses.  Resistance  at  a  synapse 
is  decreased  each  time  a  nervous  impulse  passes 
through  it,  and  an  improvement  in  conductivity  of 
the  synapse  results  from  use.    A  lessened  resistance 


98 


GENERAL  PSYCHOLOGY 


MUSCLES 


Figure  20.  establishing  a  conditioned  response,  the  first 
stimulus  that  sets  the  dog  to  running  and  harking  is  the 
sight  of  the  cat.  if,  at  the  same  time,  he  is  stimulated  by 
the  word  "cats"  pronounced  by  his  master,  the  impulses  re- 
sulting are  drained  into  the  system  that  is  acting,  and  a  new 
pathway  is  established.  after  practice,  this  sound  becomes  the 
conditioning  stimulus  that  may  set  the  dog  into 
aotmty  in  the  absence  of  any  cat 


LEARNING  99 

in  the  synapses  of  a  neural  arc  means  a  reduced 
threshold  of  response. 

The  nervous  changes  underlying  negative  adapta- 
tion are  rather  more  hypothetical.  We  may  sup- 
pose, however,  that  an  impulse  that  starts  to  tra- 
verse a  neural  arc,  but  which  does  not  reach  the 
terminal  effector,  must  of  necessity  drain  into  other 
pathways.  Any  motor  pathway,  when  active,  may 
drain  to  itself  afferent  impulses  from  other  neural 
arcs.  With  use,  drainage  pathways  become  better 
established,  with  the  result  that  later  impulses  show 
a  lessened  tendency  to  traverse  the  original  neural 
arc  and  an  increased  tendency  to  traverse  the  new 
drainage  pathway.  Thus  negative  adaptation  of 
one  response  always  means  the  substitution  of 
another  response.  This  substitution  is  brought 
about  when  drainage  establishes  new  association 
pathways.  In  this  way  impulses  from  the  stimulus 
that  is  apparently  disregarded  actually  reenforce 
some  routine  activity.  The  drained  impulses  may 
reenforce  respiration,  or  any  system  that  is  active, 
or  they  may  occasion  emotional  responses.  Thus 
they  establish  a  habit  of  doing  something  other  than 
the  act  to  which  negative  adaptation  has  been  de- 
veloped. 

Associative  Inhibition- 

If,  while  reading  aloud,  we  encounter  a  word  that 
we  have  been  in  the  habit  of  pronouncing  in  either 
of  two  ways,  a  pause  in  reading  can  be  noticed. 


100  GENERAL  PSYCHOLOGY 

This  is  because  there  are  two  pathways  of  discharge 
available  for  the  afferent  impulse.  The  two  respon- 
ses, being  incompatible,  can  not  both  be  given,  and 
mutual  inhibition  from  a  single  stimulus  is  the  re- 
sult. This  interference  is  an  event  in  the  central 
nervous  system,  and  may  occur  without  causing  a 
contraction  of  the  muscles  involved  in  either  of  the 
incompatible  responses.  Practice  of  an  incorrect 
performance  of  any  act  makes  later  learning  of  the 
act  in  its  correct  form  more  difficult  than  if  the  in- 
correct performance  had  not  occurred.  If  a  part 
of  the  multiplication  table  is  wrongly  learned,  more 
practice  of  the  correct  form  is  required  than  is  re- 
quired for  attaining  equal  facility  in  a  part  of  the 
multiplication  table  that  has  never  been  attempted. 
The  attachment  of  two  incompatible  responses  to  a 
single  stimulus,  which  results  in  their  mutual  in- 
hibition, is  called  associative  inhibition. 

The  Serial  Response 

Each  movement  a  man  makes  is  likely  to  bring  him 
into  new  relations  with  his  surroundings  and  thus 
cause  new  stimuli  to  act  upon  him.  In  this  way  a 
stimulus  produces  a  response,  this  response  a  new 
stimulus,  this  stimulus  a  new  response,  and  so  on 
until  tnere  are  no  more  stimuli  that  cause  movement. 
If  such  a  series  is  repeated  many  times,  the  man's 
responses  show  positive  adaptation  to  each  of  the 
several  stimuli,  so  that  the  time  required  for  going 


LEARNING  •  101 

through  the  series  of  responses  -is:  shortened.;*  En- 
tering our  own  house  is  an  act  we  all  'perform 
smoothly  and  quickly.  The  first  time  we  entered  the 
house,  however,  we  were  less  quick  in  opening  the 
gate  and  in  closing  it  after  us,  slower  in  mounting 
the  unfamiliar  steps,  finding  the  key,  and  unlocking 
the  front  door.  As  we  repeat  the  act  day  after  day 
our  entrance  takes  less  and  less  time.  This  increase 
in  speed  is  in  part  a  simple  positive  adaptation  of 
response  to  the  successive  stimuli  of  gate,  steps, 
key,  and  lock. 

In  addition  to  the  stimuli  that  affect  our  eyes  and 
to  which  our  responses  are  given,  there  is  another 
series  of  stimuli  that  the  responses  themselves  cause 
and  that  accompany  the  visual  stimuli.  These  are 
stimuli  to  the  proprioceptors  in  the  muscles  and  ten- 
dons caused  by  the  movements  of  manipulation  and 
walking,  and  the  stimuli  to  the  end  organs  of  touch 
that  these  movements  occasion.  These  movement- 
produced  stimuli  play  a  role  similar  to  that  of  all 
other  stimuli  that  are  incidental  to  the  actuating 
stimulus,  in  that  they  serve  to  condition  the  response 
when  the  actuating  stimulus  is  absent,  or  to  facili- 
tate the  response  when  they  occur  time  after  time 
along  with  the  actuating  stimulus.  This  facilitation 
is  a  cause  for  the  increased  speed  of  the  serial  re- 
action in  addition  to  the  positive  adaptation  men- 
tioned above. 

In  like  fashion  a  person  learns  his  way  about  the 
house,  at  first  depending  upon  his  eyes  to  avoid  ob- 


102  GENERAL  PSYCHOLOGY 

stacks  a-nd  to  find  the  easiest  route  from  place  to 
place. '  As  ail  movements  are  accompanied  by  pro- 
prioceptive stimulation,  in  time  he  is  able  to  dis- 
pense with  visual  stimuli  and  to  find  his  way  about 
in  the  dark.  Tying  a  cravat  or  lacing  a  shoe  is  at 
first  dependent  upon  visual  stimuli,  but  later  each 
component  movement  becomes  almost  wholly  condi- 
tioned by  the  Mnaesthetic  and  touch  stimuli  occas- 
ioned by  the  preceding  movement.  A  pianist  while 
learning  a  musical  composition  depends  upon  his 
score  as  a  guide  in  making  each  movement.  Later, 
because  each  movement  becomes  the  cue  to  the  next, 
because  of  its  stimulation  of  sense  organs  in  the 
muscles,  and  because  of  its  producing  sounds  that 
stimulate  the  ear,  the  musician  may  throw  away  his 
score.  If  a  printed  page  is  read  aloud  many  times, 
the  book  may  be  closed  and  the  passage  spoken  from 
memory.  This  is  in  part  the  result  of  the  sound  of 
each  word  becoming  the  conditioning  stimulus  for 
the  movements  producing  the  next  word,  and  in  part 
the  result  of  the  accompanying  kinaesthetic  stimu- 
lation playing  a  similar  role.  In  learning  to  write 
we  first  depend  upon  copy  books,  but  later,  in  addi- 
tion to  the  conditioning  proprioceptive  stimulation, 
the  sight  of  the  first  letter  of  the  familiar  word 
that  the  pen  forms  becomes  a  conditioning  stimulus 
for  writing  the  second  letter,  and  this  a  conditioning 
stimulus  for  the  third,  and  so  on.12 

12  Concerning  the  neural  basis  of  chain  reflexes  and  serial  re- 
sponses see  Herrick,  Introduction  to  Neurology,  and  Sherrington, 
Integrative  Action  of  the  Nervous  System,  p.  181ff. 


LEARNING  103 

When  a  person  is  learning  to  dance,  he  makes  one 
movement  after  another  in  response  to  each  verbal 
direction  of  his  instructor.  While  one  movement  is 
being  made  the  instructor  gives  directions  for  the 
next,  so  a  proprioceptive  stimulation  caused  by  the 
preceding  movement  accompanies  the  instructor's 
verbal  stimulus.  With  repetition  of  the  stimulus- 
response  series,  these  proprioceptive  stimuli  be- 
come conditioning  stimuli  and  serve  to  link  together 
the  responses  in  the  absence  of  verbal  direction. 
When  this  dependence  of  each  movement  upon  the 
muscle  stimulation  of  the  preceding  movement  oc- 
curs, we  say  the  person  has  learned  to  dance.  The 
way  in  which  this  substitution  of  movement-pro- 
duced stimuli  for  the  original  exteroceptive  stimuli 
comes  about  is  illustrated  in  Figure  21. 

The  facilitating  effect  of  accompanying  condition- 
ing stimuli  is  seen  in  what  might  appear  at  first  sight 
to  be  cases  of  simple  positive  adaptation.  Thus  pos- 
itive adaptation  to  the  alarm  clock  is  shown  by  the 
conscientious  person  who,  always  responding,  is 
eventually  stimulated  to  rise  by  the  faintest  tinkle. 
He  is  aided  in  rising,  however,  by  the  fact  that  his 
first  start  of  surprise  has  been  followed  by  the  move- 
ment of  his  arm  in  throwing  off  the  covers,  and  this 
in  turn  by  sitting  up,  feeling  for  his  slippers,  put- 
ting them  on,  and  rising  to  his  feet.  When  this  series 
of  movements  is  made,  'the  proprioceptive  stimuli 
occur  in  a  certain  order  and  become  conditioning 
stimuli  that  serve  to  fix  the  sequence  of  responses. 


104 


GENERAL  PSYCHOLOGY 


Positive  adaptation  plays  its  part  in  speeding 
up  each  step  in  the  chain  reaction,  but  the  most  im- 
portant factor  in  maintaining  the  response  as  a 
whole  is  the  series  of  conditioning  proprioceptive 
stimuli. 

Such  conditioning  stimuli  as  are  mentioned  above 
are  involved  in  the  movements  themselves,  and  are 
not  subject  to  the  vagaries  of  the  external  environ- 


Muscles  and 
Proprioceptors 


Figure  21.  diagrammatic  representation  of  the  formation  of  a 
serial-response  habit  (after  dunlap).  the  series  of  responses 
is  at  first  the  result  of  the  successive  stimulation  of  the 
distance  receptors  shown  at  the  top  of  the  figure.  during 
practice  this  stimulation  is  accompanied  by  the  stimulation 
of  proprioceptors  in  the  acting  muscles.  this  proprioceptive 
stimulation  gives  rise  to  nervous  impulses  that  are  drained  as 
indicated  by  the  arrows  into  tne  acting  system  and  in  time 
the  series  of  responses  may  be  elicited  by  these  movement- 
produced  stimuli,  only  the  first  of  tne  distance 
receptor  stimuli  being  necessary 

ment.  Hence  they  serve  to  stereotype  the  response 
as  a  whole  in  a  way  that  would  not  be  possible  if  the 
organism  had  to  depend  for  guidance  wholly  on  ex- 
ternal situations  whose  regular  occurrence  is  uncer- 


LEARNING  105 

tain.  These  orderly  response  series,  now  partly  in- 
dependent of  the  environment,  constitute  most  of 
our  skilled  acts  and  enable  man  with  his  aptitude 
for  such  habit  formation  to  dispense  with  the  fixed 
instinctive  order  of  responses  characteristic  of  the 
behavior  of  the  lower  animals.  This  is  not  because 
man  has  more  proprioceptors  or  other  sense  organs 
than  have  lower  animals,  but  because  in  man  these 
sense  organs  have  more  extensive  connections  in  the 
central  nervous  system.  The  resulting  plasticity  en- 
ables man  to  adjust  himself  to  various  cultures,  oc- 
cupations, and  environments. 

The  Effects  of  Practice  on  the  Serial  Response 

The  effects  of  practice  in  establishing  a  serial  re- 
sponse have  been  measured  by  Ebbinghaus,  who  de- 
termined the  number  of  repetitions  necessary  for 
learning  a  series  of  nonsense  syllables  so  that  it 
might  be  reproduced  once  without  error.  By  a  non- 
sense syllable  is  meant  such  a  sound  combination  as 
nis,  geg,  f of,  gol,  nen,  or  kev.13 

The  longer  the  series,  the  greater  is  the  number 
of  repetitions  required  for  learning.  Ebbinghaus 
could  repeat  a  series  of  seven  syllables  after  having 
said  it  once,  whereas  a  series  of  12  syllables  required 
about  16  repetitions,  a  series  of  16  syllables  required 
30  repetitions,  one  of  24  syllables,  44  repetitions,  and 

i3See:  Lyon,  Memory  and  the  Learning  Process;  Meumann,  Psy' 
chology  of  Learning ;  and  Ebbinghaus,  Memory. 


106 


GENERAL  PSYCHOLOGY 


one  of  36  syllables,  55  repetitions.    These  are  repre- 
sented in  Figure  22. 

These  results  may  be  stated  in  another  way, 
namely,  in  terms  of  the  actual  amount  of  work  done 
to  learn  each  series.     Eepeating  12  syllables  16.6 


60 


40 

1 

§20 

! 


. 

~" 

LENGTH 


10 
OF  SERIES 


20 


30 


FlGUBE  22.  TOE  NL'MBEB  OF  BEPETTTIONS  BEQUTBED  FOB  ESTABLISHING 
SEBIAL  BESPONSES  OF  YABIOtTS  LENGTHS.  THE  ItATEBIAL  LEABNED 
CONSISTED  OF  SEBIES  OF  NONSENSE  SYLLABLES.  A  BEPETITION  CON- 
SISTS OF  SAYING  ANY  SEBIES  ONCE,  IEBESPECTIVE  OF  THE  LENGTH  OF 
THE  SEBIES.  THE  SYLLABLES  WEBE  SPOKEN  AT  THE  BATE  OF 
150  A  MINUTE    (AFTEB  EBBINGHAUS) 


times  involves  pronouncing  199  syllables ;  repeating 
16  syllables  30  times  involves  pronouncing  480  syl- 
lables ;  repeating  24  syllables  44  times  involves  pro- 
nouncing 1,056  syllables ;  and  repeating  36  syllables 


LEAKNING  10? 

55  times  involves  pronouncing  1,980  syllables.  If 
we  plot  these  values  graphically,  we  find  they  lie 
approximately  on  a  straight  line.    (Figure  23). 


8UUi 1   ■  1  1  1  1  1  1  1  1  1 — i 1  1  1  1  1  1 — 1 r~T 

1    / 

If 

-\J- 

&                                                                                         t        • 

S                                                                                      /     -- 

^                          -                                                         -£. 

%           -                                                                        t 

xjroUU —  ~ — ""          -       —                —       ~t~     ~    ~ 

c&                                                                  7 

^                                                                                      V 

V            _  .                                                     Z 

c£                                                                                           J 

%                                                          -X 

E>                                                                    2 

§                                                                                     V 

T 

**U.  Anr\—~.  _  —  — _  —  —             —                   i.                                  — 

^  4UU — -           _       ,r- 

/ 

&              -                                                                t 

5g                                                                                          A 

5- 

^3                                                      J 

f°                                                   J 

W                                                 -/ 

*o                                              Z 

£kZ00    --          -                      ~jf-                        - 

f 

<t             :              i  :                     z 

Cu                                  > 

CK                                           -/ 

^                                         -J- 

^                                                v^ 

/^o                        S 

%                    -** 

<      0 ^-Tr- = =  =     ±- 

10 
LENGTH  OF  SER/ES 


20 


30 


FIGURE  23.     THE  SAME  RESULTS  ABE  SHOWN  AS  IN  FIGURE  22,  BUT  ABE 

REPRESENTED    IN    TERMS    OP    THE    ACTUAL    AMOUNT    OF    WORK    DONE    IN 

ORDER  TO  LEARN  THE  SERIES  OF  VARIOUS   LENGTHS.      EXCEPT  FOB   SERIES 

OF    LESS    THAN    12    SYLLABLES,    THE    WORK    REQUIRED    IS    A 

LINEAR  FUNCTION  OF  THE  LENGTH  OF  THE  SERIES 


This  means  that  as  we  pass  from  one  series  to 
another,  the  difference  in  the  work  required  for 


108  GENERAL  PSYCHOLOGY 

learning  is  proportional  to  the  difference  in  the 
lengths  of  the  series  learned.  If  the  syllables  are 
repeated  at  intervals  of  .4  seconds,  or  in  other  con- 
stant rhythm,  the  time  consumed  will  be  proportional 
to  the  number  of  syllables  spoken.  If  we  prepare 
series  of  nonsense  syllables  of  totally  different  mate- 
rial and  of  different  lengths,  containing  16, 17, 18, 19, 
etc.,  syllables  respectively,  and  find  that  16  syllables 
are  learned  in  3  minutes  and  17  in  3V2  minutes,  then 
the  series  of  18  syllables  will  be  learned  in  4  minutes, 
the  series  of  19  syllables  in  4%  minutes,  the  series  of 
20  in  5  minutes,  and  so  on.  It  will  then  take  13  min- 
utes to  learn  a  series  of  36  syllables. 

Even  though  it  may  be  impossible  to  remember 
to-morrow  what  we  have  learned  to-day,  to-day's 
learning  makes  to-morrow's  relearning  easier.  The 
amount  of  positive  adaptation  remaining  from  pre- 
vious practice  may  be  measured  by  the  number  of 
repetitions  saved  when  material  is  learned  over 
again.  This  method  of  measuring  retention  has  be- 
come known  as  the  saving  method. 

Ebbinghaus,  using  a  number  of  different  16-sylla- 
ble  series,  repeated  some  8  times,  some  16,  some  24, 
some  32,  some  42,  some  53,  and  some  64  times. 
Twenty-four  hours  after  each  one  was  practised  he 
found  the  number  of  repetitions  necessary  for  re- 
learning  it.  In  this  way  he  discovered  that  each  one 
of  any  number  of  repetitions  produced  the  same 
amount  of  retention  as  any  other.  It  happened  that, 
for  the  length  of  series  used,  each  of  the  original 


LEARNING  109 

repetitions  saved  the  next  day  one  per  cent  of  the 
time  that  would  have  been  required  if  there  had 
been  no  previous  practice.  Thus  8  repetitions  saved 
8.1  per  cent  of  the  next  day's  work,  32  repetitions 
saved  32  per  cent  of  the  next  day's  work,  and  53  repe- 
titions saved  53.9  per  cent.  The  fatigue  resulting 
from  many  repetitions  made  it  impossible  to  carry 
the  experiment  beyond  the  point  of  64  repetitions. 
Except  for  this,  100  repetitions  would  probably  have 
made  it  possible  to  reproduce  the  series  the  next  day 
without  any  review.  It  will  be  remembered  that  to 
learn  a  series  of  16  syllables,  so  that  it  may  be  re- 
peated once  without  error  immediately  after  the 
learning,  requires  about  30  repetitions.  Figure  24 
shows  the  relation  between  the  first  day's  practice 
and  the  next  day's  relearning. 

FOKGETTING 

If  a  given  amount  of  material  is  memorized,  we 
may  measure  the  amount  retained  in  memory  at  any 
later  time  by  finding  the  length  of  time  that  is  re- 
quired to  relearn  the  material.  The  time  saved  in 
relearning,  compared  with  the  time  required  for  the 
original  learning,  gives  us  a  quotient  that  stands  for 
the  proportion  retained  in  memory.  By  this  method 
it  is  shown  that  the  memory  deteriorates  as  time 
goes  on,  and  that  the  rate  of  deterioration  is 
most  rapid  at  the  outset.  This  rate  of  forget- 
ting as  measured  by  Ebbinghaus  is  shown  in  Figure 
25. 


110 


GENERAL  PSYCHOLOGY 


Meuraann  and  others  report  what  they  take  to  be  a 
slight  recovery  of  memory  at  the  end  of  24  hours.14 
This  anomaly  was  not  shown  in  the  careful  work  of 


800 

600 

/ 

^400 

\% 

^200 
-< 

i 

3 

0  16  32 

NUMBER  OF  ft£P£r/T/OMS 


48 


64 


FlGUBE  24.  THE  TIME  SAVED  IN  BELEABNING  A  SERIAL  RESPONSE  OF  16 
NONSENSE  SYLLABLES  SHOWN  AS  A  FUNCTION  OF  THE  AMOUNT  OF 
YESTERDAY'S  PRACTICE.  THE  AMOUNT  OF  POSITIVE  ADAPTATION  FOUND 
AT  THE  TIME  OF  RELEABNING  IS  A  LINEAR  FUNCTION  OF  THE  AMOUNT 
OF  WORK  DONE  24  HOURS  EARLIER 
(AFTER  EBBINGUAUS) 

Ebbinghaus  though  a  tendency  to  such  recovery  may 
be  noticed  in  Figure  25.  Meumann's  subjects  were 
unable  to  recall  as  much  9  hours  after  practice  as 
they  could  recall  13  hours  later.     Graphically  rep- 

i*  Meumann,  op.  tit.,  Chapter  7,  Sec.  6. 


LEARNING 


111 


resented,  there  was  a  rise  in  the  forgetting  curve 
between  the  9-  and  the  24-hour  points.    Many  suppo- 


luUfi  i  |'|  i  |  i  [  i     Mill 

_      _ 

■ 

t 

E 

Ort  [             __ 

BUR"       *" 

^       1 

$        t 

^        I 

5 

§ 

«2 

*n1 

IiiRD 

*s 

^ 

^ 

d 

fcj     It 

S     t 

• 

*£      A 

c5      !S 

K40-    ^r    - 

£               \— 

Q                   ■"BH*a»*fc« 

<o                                   ***«» 

o*        — 

iS 

$      - 

S. 

20  —                         —        —  —  —  — 

-"0    HOURS      20 

40           *            60 

FIGURE  25.      THE  RATE  OP  FORGETTING  A  NONSENSE   SERIES    (AFTER   EB- 

BINGHAUS).      THE  AMOUNT  OF  POSITIVE   ADAPTATION   REMAINING 

AT  ANY  TIME  IS  MEASURED  BY  THE  SAVING  METHOD 

sitions  have  been  made  on  the  basis  of  these  results. 
Colvin  says  "this  improvement  in  memory  seems  to 


112  GENERAL  PSYCHOLOGY 

be  due  to  the  fact  that  the  original  impressions  have 
had  an  opportunity  to  become  associated  with  per- 
manent elements  in  consciousness,  and,  therefore, 
are  capable  of  revival  more  readily  after  a  certain 
lapse  of  time."  15 

From  the  following  experiments  by  W.  R.  Wilson 
in  the  local  laboratory  an  interpretation  of  Meu- 
mann's  results  in  terms  of  the  facilitating  action  of 
conditioning  stimuli  is  suggested.  Ten  subjects 
learned  lists  of  ten  nonsense  syllables,  and  72  hours 
later  relearned  the  same  lists  sometimes  in  the  same 
surroundings,  and  sometimes  in  different  surround- 
ings. Each  subject  learned  one  list  in  the  labora- 
tory and  relearned  in  the  laboratory,  learned  a  sec- 
ond list  in  the  laboratory  and  relearned  out  of  doors, 
learned  a  third  list  out  of  doors  and  relearned  in  the 
laboratory,  and  learned  a  fourth  list  out  of  doors  and 
relearned  out  of  doors.  In  eight  of  the  ten  subjects 
there  was  greater  saving  in  each  case  where  re- 
learning  occurred  in  the  same  surroundings  in  which 
the  first  learning  had  taken  place.  Two  subjects 
showed  in  one  of  their  four  series  a  greater  saving 
where  relearning  had  occurred  under  dissimilar  con- 
ditions. An  average  of  11.4  per  cent  fewer  repeti- 
tions were  required  to  relearn  in  similar  surround- 
ings. 

In  another  experiment  the  subject  was  seated  in 
a  room  and  copied  a  list  of  letters  on  a  typewriter 
whose  keys  had  been  arranged  in  a  random  order. 

!5  Colvin,  The  Learnitig  Process,  p.  140. 


LEARNING  113 

He  copied  the  same  list  24  hours  later  and  the  times 
were  compared.  A  variable  condition  consisting  of 
the  presence  or  absence  of  the  odor  of  oil  of  pepper- 
mint was  used.  Each  subject  practised  a  list  with 
the  odor  present  and  repeated  the  same  list  with 
the  odor  absent;  he  then  practised  a  list  with  the 
odor  present  and  repeated  the  list  24  hours  later  with 
the  odor  present.  He  then  practised  the  list  without 
the  odor  and  repeated  with  the  odor;  and  last  prac- 
tised without  the  odor  and  repeated  without  the 
odor.  Thirteen  subjects  were  used,  and  the  aver- 
age saving  in  the  time  required  to  repeat  the  list  was 
9.4  per  cent  greater  when  the  repetition  took  place 
under  the  condition  of  the  first  practice. 

It  is  highly  probable  that  the  greater  retention 
shown  by  Meumann's  subjects  at  the  end  of  24  hours 
depended  upon  the  daily  recurrence  of  conditioning 
stimuli.  There  is  a  diurnal  rhythm  of  experience 
that  results  in  a  characteristic  internal  state  at  each 
hour  of  the  day.  We  sleep,  eat,  work,  and  play  ac- 
cording to  a  fairly  rigid  schedule.  The  resulting 
periodic  bodily  states,  present  at  the  original  learn- 
ing, contribute  familiar  stimuli  to  anyone  who  is  en- 
gaged in  relearning  after  a  24-hour  period.  These 
stimuli  come  to  condition  the  responses  and  facili- 
tate the  relearning. 

Whole  and  Pakt  Learning 

One  of  the  practical  questions  that  arise  when  we 
have  something  to  commit  to  memory  is  whether  the 


114  GENERAL  PSYCHOLOGY 

material  should  be  rehearsed  from  beginning  to  end, 
or  broken  up  into  parts  so  that  each  part  can  be 
learned  separately  and  the  parts  later  combined.  If 
the  law  represented  by  Figure  23  held  for  short 
series  as  well  as  for  long,  it  would  take  approxi- 
mately twice  the  time  to  learn  any  series  as  to  learn 
a  series  half  that  length.  Part  learning  would  then 
evidently  be  wasteful,  because  it  would  take  the  same 
time  to  learn  by  parts  as  to  learn  by  wholes,  and 
after  the  parts  were  learned  the  order  of  the  parts 
would  have  to  be  learned  also.  The  law  (Figure  23) 
holds,  however,  only  for  lengths  somewhat  greater 
than  the  memory  span.  This  memory  span  is  the 
amount  that  can  be  accurately  reproduced  after  a 
single  reading.  Because  very  small  parts  are  mem- 
orized with  relatively  greater  ease  than  large  parts, 
we  have  no  way  of  determining  in  advance  of  expe- 
riment whether  the  easy  learning  of  small  parts 
compensates  for  the  necessity  of  linking  these  parts 
together  after  each  has  been  committed  to  memory. 
Ebbinghaus  has  shown  that  when  two  series  of 
different  lengths  are  memorized  to  the  point  of  one 
perfect  reproduction,  the  longer  series  is  better  re- 
tained after  24  hours  than  is  the  shorter  series. 
Thus,  33  per  cent  of  a  12-syllable  series  is  shown  by 
the  saving  method  to  persist  after  the  lapse  of  one 
day,  whereas  48  per  cent  of  a  24- syllable  series  is 
retained.  This  fact,  taken  in  conjunction  with  the 
law  (Figure  23)  that  an  increase  in  the  length  of  the 
series   demands   a   corresponding   increase   in   the 


LEARNING  115 

amount  of  work  required  for  learning,  gives  us  rea- 
son to  expect  that  experimental  results  will  show  a 
saving  when  the  method  of  learning  by  wholes  is  em- 
ployed. 

Experimental  results  demonstrate  conclusively 
that  part  learning  is  wasteful  and  whole  learning 
most  efficient.  The  whole  method  requires  less  work 
for  a  single  accurate  reproduction,  and  for  a  given 
amount  of  work  done  results  in  fewer  errors  and  bet- 
ter retention.  This  holds  true  for  both  nonsense 
material  and  for  meaningful  material.18 

The  word  "learning"  is  here  used  in  the  sense  of 
verbatim  memorizing  where  only  serial  responses 
are  practised.  In  such  a  subject  as  geometry,  the 
laws  of  whole  and  part  memorizing  do  not  apply. 
This  kind  of  learning  will  be  considered  in  the  chap- 
ter on  perception. 

Results  of  the  Distribution  of  Peactice 

If  we  have  a  certain  amount  of  time  to  spend  in 
memorizing,  it  is  found  advantageous  to  distribute 
this  time  over  several  days  rather  than  to  utilize  it 
all  at  one  sitting.  Ebbinghaus  found  that  a  12-syl- 
lable  series  repeated  68  times  consecutively  required 
7  repetitions  for  relearning  24  hours  later.  Series  of 
the  same  length  repeated  on  an  average  of  17.5  times 


16  Lyon,  op.  cit.;  Pechstein,  Whole  vs.  Part  Methods  tn  Motor 
Learning,  Psychological  Monographs,  1917;  Pyle,  "Economical 
Learning,"  Journal  of  Educational  Psychology,  1913,  pp.  148-158; 
Pyle  and  Snyder,  "The  Most  Economical  Unit  for  Committing  to 
Memory,"  ibid.,  1911,  pp.  133-142. 


116  GENERAL  PSYCHOLOGY 

the  first  day,  12  times  the  second  day,  and  8.5  times 
the  third  day  (38  in  all  as  against  68)  needed  but  5 
repetitions  for  relearning  on  the  fourth  day.  It  is 
evident  from  this,  and  from  similar  results  that  have 
been  found  for  meaningful  material,  that  economy 
of  learning  demands  distributed  repetitions. 

Lashley  has  shown  that,  in  training  white  rats  to 
choose  the  path  leading  to  food,  using  two  trials  a 
day  saved  69  per  cent  of  the  work  that  would  have 
been  necessary  if  ten  trials  a  day  had  been  used.17 

Learning  Meaningful  Material 

Learning  a  prose  passage  verbatim,  committing 
verse  to  memory,  or  learning  to  say  a  set  of  non- 
sense syllables  as  in  Ebbinghaus'  experiments,  is  the 
acquisition  of  serial  response  habits.  When  the 
practice  begins,  each  printed  symbol  is  the  stimulus 
for  a  response  that  has  been  already  attached  to 
this  symbol  by  conditioning.  As  the  stimuli  occur  in 
a  given  order,  the  reactions  follow  each  other  in  a 
given  order,  and  with  a  sufficient  number  of  repeti- 
tions the  serial  response  is  established  independent 
of  visual  stimuli  but  dependent  upon  proprioceptive 
and  auditory  stimuli. 

In  learning  nonsense  syllables  the  learner  is 
wholly  unaccustomed  to  the  order  of  the  responses, 
and  the  whole  of  the  series  must  be  learned.    In  deal- 

—  ■  

M  Lashley,  "A  Simple  Maze;  with  data  on  the  relation  of  the  dis- 
tribution of  practice  to  the  rate  of  learning,"  Psychobiology,  1918, 
pp.  353-367. 


LEARNING  117 

ing  with  words,  on  the  other  hand,  the  learner  is 
seldom  without  some  previous  experience  of  their 
sequence,  and  when  committing  to  memory  ordinary 
prose  he  relies  very  largely  upon  already  formed 
serial  response  habits.  Familiarity  makes  relatively 
easy  his  remembering  combinations  of  "sensible" 
words.  The  meaningfulness  of  language  is  a  fur- 
ther aid  to  prose  learning.  This  aid  is  partly  com- 
posed of  gesture  and  characteristic  emotional  ex- 
pression, of  customary  pitch,  speed,  and  intensity 
variations  of  the  voice.  The  response  tendencies 
that  are  touched  off  by  each  of  the  spoken  words 
also  play  their  part  in  the  reenforcement. 

Some  prose  is  easy  to  commit  to  memory,  whereas 
other  prose  is  difficult.  Easy  prose  contains  stero- 
typisms  and  familiar  word  combinations.  Less  stu- 
pid and  more  original  texts  combine  words  in  a  less 
predictable  order,  and  so  are  more  difficult  to  memo- 
rize or  even  to  read.  Verse  is  easy  to  learn  on  ac- 
count of  its  set  rhythm  and  its  predictable  end 
rhymes. 

Trial  and  Error 

Certain  organisms,  such  as  paramoecium,  have 
for  the  most  part  but  a  single  manner  of  response. 
This  is  given  to  every  harmful  situation  the  animal 
meets  in  its  forward  swimming  and  consists  in  back- 
ing, turning  to  one  side,  and  then  proceeding  in  a 
new  direction.    If  this  response  brings  it  again  into 


118  GENERAL  PSYCHOLOGY 

harmful  conditions,  the  response  is  repeated  until 
the  animal,  is  progressing  through  a  medium  that 
contains  no  stimuli  for  this  avoidance  reaction. 
When  an  animal  makes  many  trials,  any  one  of  which 
may  or  may  not  be  specially  fitted  to  remove  the 
animal  from  harm  or  bring  it  into  better  surround- 
ings, and  when  as  a  result  of  these  trials  it  finally 
stumbles  upon  the  suitable  response,  its  behavior  is 
called  trial  and  error.16 

Trial  and  error  enters  into  the  behavior  of  all  ani- 
mals. When  hungry,  they  are  likely  to  range  about 
until,  after  many  fruitless  reactions,  they  come  at 
last  by  chance  upon  food  or  the  signs  of  food.  In 
the  same  way  mates  are  discovered,  new  shelter  is 
found,  or  building  materials  secured.  The  trial  and 
error  behavior  of  most  higher  animals  differs  from 
that  of  the  lowest  forms  in  exhibiting  not  one  but 
many  different  kinds  of  response.  If  we  place  a 
cat  in  a  " puzzle  box,"  the  door  of  which  opens  only 
when  the  cat  pulls  a  string  or  turns  a  knob,  the  cat 
will  make  many  kinds  of  unsuccessful  movement  be- 
fore it  accidentally  hits  upon  the  proper  means  of 
escape. 

Most  inventions  and  discoveries  are  the  result  of 
happy  accidents.  Charles  Lamb's  hypothesis  of  the 
origin  of  roast  pig  is  not  wholly  fanciful.  We  may 
be  certain  that  the  discovery  of  intoxicating  bev- 
erages was  due  to  the  carelessness  of  some  primitive 

!8  Thorndike,  Animal  Intelligence,  p.  35ff;  Jennings,  Behavior  of 
Lower  Organisms. 


LEARNING  119 

housewife  who  allowed  her  fruit  to  spoil  but  whose 
frugality  prompted  a  reluctant  use  of  a  concoction 
whose  hidden  possibilities  must  soon  have  had  a 
wide  publicity. 

A  series  of  trial  and  error  responses  may  become 
a  habit  in  certain  cases  through  the  agency  of  con- 
ditioning stimuli  in  the  manner  described  in  the 
discussion  of  serial  responses.  It  is.  very  seldom, 
however,  that  the  series  of  trial  and  error  responses 
as  a  whole  becomes  fixed  as  a  habit.  Usually  the 
series  is  shortened  in  the  process  of  habit  formation, 
the  final  response  being  given  but  many  of  the  futile 
responses  that  preceded  it  being  eliminated.  We 
may  now  ask  the  question  how  this  shortening  of 
the  series  is  accomplished. 

The  Shortening  of  a  Trial  and  Error  Series  into 
a  Final  Habit  Response 

When  considering  the  subject  of  threshold  of  re- 
sponse we  found  that  a  stimulus  may  be  too  weak 
to  elicit  any  movement.  When  a  stimulus  is  above 
the  threshold,  the  kind  of  reaction  it  causes  may 
depend  upon  its  intensity.  It  is  a  general  principle 
that  most  stimuli,  which  when  weak  cause  an  ap- 
proach reaction,  cause  avoidance  when  they  become 
very  intense.  This  is  illustrated  by  taste  stimuli. 
The  sourness  of  lemonade  and  the  bitterness  of 
coffee  can  be  increased  to  a  point  where  these  drinks 
are  avoided.    A  limited  amount  of  salt  is  necessary 


120  GENERAL  PSYCHOLOGY 

to  make  eggs  palatable,  but  when  exceeded  causes 
avoidance.  Children  instinctively  seek  sweet  food, 
but  food  may  be  so  sweet  as  to  become  disgusting. 
The  resistance  that  a  little  child  shows  to  rough 
handling  may  be  replaced  by  acquiescence  to  gentle 
manipulation.  The  baby  accepts  more  readily  the 
nipple  of  his  nursing  bottle  when  it  is  gently  placed 
in  his  mouth  than  when  it  is  forcibly  inserted. 

The  response  that  a  new-born  baby  gives  to  a 
stimulus  is  definitely  determined  by  the  innate  struc- 
ture of  his  nervous  system,  although  there  may  be 
minor  fluctuations  of  response  in  the  same  infant  at 
different  times  due  to  such  physiological  changes  as 
hunger  or  fatigue.  His  response  tendencies  are  in 
large  part  predictable.  He  naturally  responds  by 
grasping,  looking,  withdrawing,  or  other  movements 
according  to  the  nature  of  the  stimulus.  Thus  ap- 
proach and  avoidance  are  not  chance  behavior,  and 
the  fact  that  all  people  learn  in  much  the  same  way 
is  due  to  their  being  equipped  to  respond  to  a  given 
stimulus  by  the  same  reaction.  Many  of  these  re- 
actions are  simple  reflexes. 

The  more  remote  an  object  is,  the  less  intense  is 
its  stimulation,  and  approach  to  the  object  gradually 
increases  the  intensity  of  this  stimulation.  In  cer- 
tain cases  an  intensity  may  be  reached  that  causes  a 
turning  away.  Thus  the  increasing  stimulation  of  a 
single  sense  organ  often  results  successively  in  op- 
posite orientations. 

Another  frequent  result  of  approaching  an  object 


LEARNING  121 

is  to  bring  stimuli  to  bear  upon  sense  organs  not  at 
first  affected.  A  single  object  may  be  the  source  of 
stimuli  first  to  distance  receptors,  such  as  eyes,  ears, 
or  nose,  and  later  to  the  sense  organs  in  the  skin, 
muscles,  and  tendons.  When  a  deer  approaches  at 
the  sight  of  a  man,  not  only  does  the  visual  stimulus 
increase  in  intensity,  thus  tending  to  make  the  deer 
take  flight,  but  its  greater  proximity  to  the  man 
brings  into  play  odor  stimuli,  in  response  to  which 
the  deer  turns  away.  This  succession  of  approach 
and  avoidance  is  characteristic  of  most  trial  and 
error  behavior.19 

The  incompatibility  between  approach  and  avoid- 
ance is  for  the  most  part  an  incompatibility  of  ori- 
entations. The  movements  of  locomotion  made  by 
the  deer  are  not  fundamentally  different  in  approach 
and  in  retreat.  The  difference  lies  in  the  direction 
in  which  the  deer  is  turned.  This  makes  evident 
the  importance  of  the  analysis  of  movement  groups 
into  their  component  parts. 

There  is  a  classical  example  of  the  baby  and  the 
candle.  The  baby  seeing  the  flame  approaches  his 
finger,  and  on  feeling  the  flame  withdraws  his  finger. 
If  charged  wires  are  placed  before  the  opening  of 
a  rat's  food  box,  so  that  the  animal  in  stepping  upon 
them  receives  a  mild  punishment,  his  approach  is 
followed  by  avoidance.  If  a  bird  takes  a  bite  of  a 
cinnabar  caterpillar,  the  taste  makes  it  reject  the 

19  Holmes,  Studies  in  Animal  Behavior,  Chapter  VII ;  Watson,  op. 
cit.,  Chapter  8. 


122  GENERAL  PSYCHOLOGY 

food.  A  master  who  does  not  enjoy  the  friendly 
greeting  of  the  dog  that  places  his  dirty  forepaws 
on  clean  clothing,  causes  the  dog  to  desist  by  step- 
ping on  the  hind  feet  of  the  animal.  In  all  these 
cases  while  the  approach  stimulus  is  still  present, 
the  avoidance  reaction  has  been  called  forth.  The 
result  is  that  the  avoidance  reaction  is  now  condi- 
tioned by  the  approach  stimulus,  so  that  on  the  next 
occasion  the  avoidance  response  tends  to  be  given  as 
soon  as  the  approach  stimulus  is  received.  The  sight 
of  the  flame  has  become  the  conditioning  stimulus 
for  withdrawing  the  finger.  The  sight  of  the  door 
of  the  food  box  has  become  the  conditioning  stimulus 
for  turning  away.  The  sight  of  the  caterpillar  has 
become  the  conditioning  stimulus  for  rejecting  the 
food.  The  sight  of  the  master  has  become  the  con- 
ditioning stimulus  for  returning  to  all  fours.  In 
addition  to  the  conditioning  visual  stimuli  involved 
in  these  responses,  the  proprioceptive  stimuli 
brought  about  by  the  approach  movements  serve  to 
condition  the  movements  of  withdrawal. 

It  is  obviously  impossible  for  the  baby  to  extend 
and  withdraw  its  hand  at  the  same  time,  for  the  rat 
simultaneously  to  approach  and  retreat  from  the 
door,  for  the  bird  to  eat  its  caterpillar  while  reject- 
ing it,  or  for  the  dog  to  paw  his  master  while  back- 
ing away.  The  interference  of  these  opposed  move- 
ments may  not,  on  the  second  occurrence  of  the  ap- 
proach stimulus,  prevent  the  succession  of  approach 
and  avoidance,  but  eventually  repetition  establishes 


LEARNING  123 

the  conditioned  response  more  firmly,  so  that  in  the 
end,  provided  the  avoidance  stimulus  is  sufficiently- 
strong,  the  approach  response  ceases  to  be  given. 
This  is  due  to  the  gradual  lowering  of  threshold  of 
the  avoidance  response  as  elicited  by  the  approach 
stimulus  and  the  resulting  mutual  inhibition  of  the 
two  opposed  response  tendencies.  When  this  occurs, 
we  say  the  baby  is  trained  to  avoid  the  candle,  the 
rat  to  avoid  the  door,  the  bird  to  let  the  caterpillar 
alone,  and  the  dog  to  proper  conduct. 

Emotional  reenforcement  is  usually  associated  in- 
stinctively with  avoidance  responses.  Running  away 
is  accompanied  by  fear;  rejecting  food,  by  nausea; 
averting  the  eyes,  by  disgust  or  shame ;  withdrawing 
the  burnt  hand,  by  grief;  turning  away  from  in- 
superable obstacles,  by  annoyance.  The  responses 
to  all  pain  stimuli  are  emotionally  facilitated.  This 
emotional  reenforcement  makes  avoidance  relatively 
more  energetic  than  approach,  and  so  in  the  rivalry 
of  two  incompatible  responses  it  is  likely  to  prevail. 

The  approach  responses  in  mating  and  food-getting 
have  strong  emotional  reinforcements.  Thus,  be- 
cause of  appetite,  these  approach  movements  are 
often  carried  out  to  the  disregard  of  stimuli  that 
would  otherwise  cause  withdrawal.  Negative  adap- 
tation to  the  disregarded  avoidance  stimuli  then  oc- 
curs. Within  certain  limits,  the  longer  the  period 
of  fasting  or  continence,  the  greater  is  the  emotional 
reenforcement  and  the  more  aggressive  the  approach 
movements.    This,  along  with  the  fact  that  abortive 


124  GENERAL  PSYCHOLOGY 

behavior  of  this  sort  calls  out  further  emotional  re- 
enforcement,  assures  the  final  success  of  food-getting 
and  mating. 

Let  us  consider  again  the  case  of  a  cat  placed  in 
the  puzzle  box.  After  many  fruitless  movements  he 
is  attracted  by  the  button,  the  turning  of  which  opens 
the  door.  After  the  cat  has  been  placed  repeatedly 
in  the  box,  the  time  required  for  escape  becomes 
gradually  less,  and  the  fruitless  movements  grow 
fewer,  until  finally  the  cat's  being  placed  in  the  box 
may  be  followed  at  once  by  the  successful  response 
of  turning  the  button. 

The  cat  when  in  confinement  is  instinctively  organ- 
ized to  respond  to  the  sight  of  bars,  cracks,  corners, 
and  even  solid  walls  by  approaching  and  pulling  and 
pushing  with  paws,  claws,  nose,  and  teeth.  If  any 
part  of  the  box  is  loose,  the  cat  has  a  tendency  to 
continue  his  manipulation.  He  is  also  instinctively 
organized  to  turn  away  from  these  same  objects 
when  they  offer  more  than  a  certain  amount  of  re- 
sistance to  his  attack. 

The  situations  the  cat  faces  in  the  puzzle  box  are 
composed,  for  the  most  part,  of  visual  stimuli  that 
attract  him,  followed  by  stimuli  to  his  proprio- 
ceptors and  sense  organs  of  touch  that  repel  him, 
and  these  two  classes  of  stimuli  are  given  by  the 
same  object.  He  is  instinctively  attracted  by  the 
sight  of  the  bars,  but  on  reaching  them,  especially 
if  they  are  rigid,  he  is  instinctively  impelled  to  turn 
away.    This  turning  away  is  due  to  the  resistance  of 


LEARNING  125 

the  bars  to  his  attempted  manipulation  and  to  his 
efforts  to  force  his  way  between  them.  Approach 
and  retreat  are  here  original  tendencies  called  forth 
by  a  single  object. 

With  repetition  the  sight  of  the  bars  becomes  the 
conditioning  stimulus  for  retreat,  so  that  the  condi- 
tioned response  inhibits  the  original  response.  One 
by  one  the  movements  of  approach  to  the  various 
confining  surfaces  of  the  box  are  inhibited  by  the 
conditioned  responses  of  retreating,  until  at  last  the 
animal  is  attracted  by  the  door-opening  device.  The 
reason  that  this  last  movement  is  not  inhibited  is 
that  the  device  itself  never  serves  as  the  source  of 
a  stimulus  that  is  instinctively  avoided.  Although 
the  cat  turns  away  from  the  button  in  response  to 
the  open  door,  he  does  so  not  because  the  button 
repels  him  but  because  the  open  door  attracts  him. 
Approaching  the  button  and  approaching  the  open 
door  are  the  only  approach  responses  that  are  un- 
inhibited by  conditioned  avoidance  responses,  and, 
while  the  door  is  closed,  the  button  alone  calls  forth 
an  uninhibited  response. 

When  the  cat  is  but  partially  trained,  he  makes 
useless  responses  to  various  parts  of  the  box.  He 
always  ends,  however,  by  making  the  successful  re- 
sponse and  by  escaping.  As  some  useless  responses 
are  given  on  some  occasions  and  others  on  other  oc- 
casions, depending  upon  the  cat's  chance  position 
in  the  box,  the  successful  response,  always  occurring, 
is  likely  to  be  the  one  most  practised.    This  may  be 


126  GENERAL  PSYCHOLOGY 

another  factor  in  lowering  the  threshold  of  response" 
to  the  door-opening  device.20 

Mutual  inhibition  of  two  incompatible  response 
tendencies  may  result  from  other  kinds  of  situations 
than  one  in  which  the  same  object  furnishes  both 
approach  and  avoidance  stimuli.  If  a  dog  is  tickled 
on  both  sides  simultaneously,  the  usual  scratch  re- 
flex may  be  elicited  from  neither  side.21 

Here  two  approach  responses  serve  to  inhibit  each 
other  because  the  tickling  of  each  side  produces  a 
contralateral  extension  of  the  hind  leg,  as  well  as 
the  oscillatory  scratching  movements  of  the  leg  on 
the  side  stimulated.  As  both  legs  are  actuated  both 
to  scratch  and  to  support  by  the  bilateral  stimula- 
tion, and  as  these  movements  are  incompatible,  there 
may  result  either  no  movement  at  all  or,  because  of 
the  unstable  equilibrium  of  this  system,  an  alterna- 
tion of  scratching  on  the  two  sides.  It  is  only  this 
unstable  equilibrium  that  makes  incredible  the  case 
of  Buridan's  ass,  who,  the  victim  of  balanced  ap- 
proach tendencies,  starved  while  standing  between 
two  stacks  of  hay. 

A  more  stable  equilibrium  is  found  where  an  ani- 
mal is  hemmed  in  by  avoidance  stimuli.  The  cat 
hesitates  to  take  to  the  water  when  pursued  by  a 
dog.  The  victim  in  a  burning  building  is  repelled 
by  both  the  fire  and  the  long  drop  to  the  street.    In 


20  Smith,  "The  Limits  of  Educability  in  Paramoecium,"  Journal  of 
Comparative  Neurology  and  Psychology,  1008,  p.  503. 
2i  Sherrington,  op  cit.,  p.   143. 


LEARNING  127 

daily  life  we  are  often  placed  between  the  devil  and 
the  deep  sea. 

When  trial  and  error  behavior  does  not  involve 
avoidance  responses,  many  fruitless  movements  may 
be  retained  in  the  resulting  habit.  The  self-educated 
bricklayer  is  likely  to  preserve  many  superfluous 
motions  that  are  the  results  of  the  chance  arrange- 
ment of  his  materials  at  the  time  he  first  began  to 
learn  the  trade.  If  an  inconveniently  placed  brick, 
or  an  awkward  manner  of  handling  his  trowel,  had 
always  been  the  stimulus  for  an  avoidance  response, 
as  of  course  it  occasionally  is,  he  would  not  have 
developed  his  unskillful  and  costly  habit.  The  in- 
struction a  bricklayer  receives  consists  in  verbal 
directions  and  criticisms  that  compensate  for  the 
absence  of  innate  avoidance  stimuli.  The  same  is 
true  of  learning  a  golf  stroke,  learning  to  play  a 
violin,  or  learning  to  sing.  In  social  behavior  the 
moral  code  in  the  absence  of  avoidance  stimuli  serves 
to  inhibit  acts  that  endanger  common  welfare,  leav- 
ing free  from  interference  only  acts  of  virtue. 

The  reason  that  such  habitual  serial  responses  as 
signing  one's  name,  whistling  a  melody,  or  reciting 
a  poem,  undergo  no  shortening  by  the  omission  of 
responses  is  that  these  acts  do  not  bring  avoidance 
stimuli  into  play. 

It  has  been  pointed  out  before  that  many  acts  are 
made  up  of  movements  of  orientation,  locomotion, 
and  intervention.  It  is  not  necessary  that  orienta- 
tion should  be  complete  before  locomotion  begins,  or 


128  GENERAL  PSYCHOLOGY 

that  locomotion  should  be  finished  before  movements 
preparatory  to  intervention  are  commenced.  In 
such  a  practised  act  as  picking  up  a  book  from  the 
floor,  we  do  not  first  turn  toward  the  book,  then 
walk  to  the  spot,  bend  the  body,  extend  the  arm, 
and  grasp  the  book,  all  separately.  We  are  more 
likely  to  start  walking  as  we  turn,  bend  the  body 
and  extend  the  arm  as  we  walk,  and,  while  grasping 
the  book,  turn  the  body  preparatory  to  walking 
away. 

When  a  number  of  acts  form  a  serial  response, 
one  act  is  seldom  completed  before  the  next  is  be- 
gun. In  this  way  there  is  an  overlapping  of  compati- 
ble movements,  orientation  for  the  next  act  occur- 
ring while  the  movements  of  intervention  of  the  last 
act  are  still  in  progress.  This  telescoping  of  one  act 
with  another  is  one  of  the  factors  in  shortening  the 
time  of  a  serial  response. 

Where  overlapping  of  acts  occurs,  more  move- 
ments are  made  at  the  same  time,  and  so  more  move- 
ment-produced conditioning  stimuli  are  available  to 
knit  together  the  parts  of  the  series. 

As  a  series  of  acts  is  repeated  time  and  again, 
the  degree  of  overlapping  of  the  individual  acts  in- 
creases more  and  more,  until  limited  by  the  ana- 
tomical structure  of  the  animal  or  by  the  require- 
ments of  the  situation.  This  overlapping  is  made 
possible  by  the  fact  that  many  conditioning  stimuli 
have  been  acting  for  some  time  before  the  response 
that  they  have  come  to  condition  has  occurred.    As 


LEARNING  129 

we  approach  a  door  and  finally  see  the  keyhole  we 
reach  for  our  keys.  Later,  because  we  saw  the  door 
while  reaching  for  the  keys,  we  take  out  our  keys 
when  we  first  come  in  sight  of  the  door.  Reaching 
for  one's  keys  having  been  established  as  a  response 
to  the  sight  of  the  door,  may  occur  while  opening  the 
gate,  provided  the  door  is  in  view.  Thus  the  re- 
sponse may  next  be  conditioned  by  the  gate  opening, 
and  later  still  by  the  sight  of  the  gate  in  the  distance. 

In  the  same  way,  because  of  the  overlapping  of 
the  parts  of  situations,  a  dog  first  responds  to  the 
sight  of  members  of  the  family,  then  to  their  foot- 
steps, then  to  the  sound  of  the  train  on  which  they 
regularly  arrive. 

Ease,  grace  of  movement,  or  the  facile  perform- 
ance of  a  difficult  act  does  not  come  with  maturity 
alone,  but  requires  practice.  Coordinated  move- 
ments are  guided  by  stimuli  in  the  external  situation, 
or  by  stimuli  that  are  movement-produced.  Each 
movement  is  attached  to  its  stimulus  by  original 
nature  or  by  conditioning,  and  the  proper  energy 
of  each  movement  is  learned  by  trial  and  error.  In 
picking  up  a  brick  we  grip  it  sufficiently  to  keep  it 
from  slipping  out  of  the  hand,  take  up  a  posture  that 
prevents  our  being  overbalanced  by  the  weight,  and 
lift  with  sufficient  force  to  raise  the  brick  from  the 
ground.  In  the  process  of  learning,  the  brick  and 
each  antecedent  movement  furnish  the  conditioning 
stimuli  for  each  part  of  the  act.  We  employ  a  very 
different  prehension,  posture,  and  lift  in  picking  up 


130  GENERAL  PSYCHOLOGY 

a  sponge.  We  are  not  conscious  of  this  difference 
in  behavior  unless  the  object  we  pick  up  has  a  de- 
ceptive appearance. 

Awkwardness  is  eliminated  by  trial  and  error,  and 
by  the  dropping  out  of  incompatible  movements  that 
constitute  mistakes.  We  adjust  the  force  of  mus- 
cular contractions  to  the  work  that  is  to  be  done. 
Such  adjustments,  together  with  the  elimination  of 
false  moves  and  the  telescoping  of  successive  acts, 
results  in  a  maximum  simplicity  of  the  effective  re- 
sponse, and  this  we  call  coordination,  or  eusynergia. 

The  nervous  structure  that  governs  many  coordi- 
nated acts  is  a  matter  of  original  nature  alone. 
Birds  and  insects  fly  without  practice;  the  baby 
balances  on  his  two  feet  by  means  of  a  neural 
mechanism  that,  though  it  improves  with  use,  is  an 
endowment  of  great  effectiveness;  nursing  move- 
ments occur  in  an  orderly  combination  and  sequence. 
The  extent  to  which  the  cerebral  cortex  is  involved 
in  learned  coordination  where  the  sequence  of  move- 
ments is  independent  of  stimuli  remains  somewhat 
a  matter  of  conjecture.  It  is  not  probable,  however, 
that  an  elaborate  series  of  movements  may  be  coor- 
dinated by  cortical  processes  independent  of  move- 
ment-produced stimuli. 

Imitation 

When  a  response  resembles  its  stimulus,  we  call 
the  response  imitation.    We  laugh  on  hearing  others 


LEARNING  131 

laugh.  A  fright  response  spreads  from  individual 
to  individual  in  the  herd.  One  sheep  jumps  the  fence 
because  the  preceding  sheep  jumped  it.  The  barking 
of  one  dog  causes  all  the  dogs  of  the  neighborhood 
to  join  in.  On  seeing  a  person  studying  the  sky  we 
stop  and  do  likewise.  When  a  cage  of  pigeons  is 
supplied  with  water,  the  water  may  not  be  noticed 
for  some  time,  but  when  one  pigeon  begins  to  drink, 
several  others  will  usually  perform  the  same  act. 
Smoking,  yawning,  whistling,  throwing  stones  at  a 
target,  rising  and  going  home,  hissing  and  applaud- 
ing, are  stimuli  that  readily  call  out  imitation  in 
others. 

Tickling  is  probably  the  original  stimulus  that 
causes  a  baby  to  smile.  He  does  not  at  first  smile 
by  imitation,  but  in  order  to  learn  to  imitate  he 
must  have  someone  present  to  smile  back  at  him. 
If  the  sight  of  a  smiling  face  accompanies  the  baby's 
act  of  smiling,  it  thereby  conditions  his  response 
and  will  later  cause  him  to  smile  in  the  absence  of 
tickling. 

Practically  all  imitative  behavior  is  made  up  of 
conditioned  responses,  there  being  very  few  cases  of 
instinctive  imitation.  These  few  cases  are  prob- 
ably limited  to  the  tendency  of  lower  animals  to 
run,  swim,  and  fly  together,  to  orient  themselves  in 
the  same  direction,  and  to  follow  one  another.  The 
instinct  of  following  is  very  often  the  act  of  ap- 
proaching something  that  is  moving  away.  This 
analysis  applies  rather  to  the  following  of  fawns, 


132  GENERAL  PSYCHOLOGY 

kittens,  and  puppies  than  to  the  following  of  chicks. 
In  the  case  of  the  fawn  that  follows  its  mother  in 
her  flight  the  approach  response  is  very  evident, 
for  when  the  mother  stops,  the  fawn  nestles  against 
her. 

The  dependence  of  imitation  on  learning  is  well 
illustrated  by  language  acquisition.  The  baby  is  at 
first  moved  to  make  a  great  variety  of  vowel  and 
consonant  sounds  by  such  stimuli  as  he  receives  from 
a  moderately  full  stomach,  a  soft  bed,  and  a  warm, 
well  lighted  room.  The  sounds  he  makes  accompany 
the  movements  that  produce  them  and,  because  the 
vowels  are  sustained  and  the  consonants  either  sus- 
tained or  repeated,  these  sounds  also  precede  the 
movements  that  continue  or  reiterate  them.  They 
thus  become  the  conditioning  stimuli  for  their  own 
production,  so  that  when  uttered  by  others  they  are 
imitated  by  the  baby.  A  period  of  practice,  during 
which  the  baby  plays  with  these  sounds,  is  neces- 
sary before  imitation  is  possible,  and  by  this  prac- 
tice the  baby  is  prepared  to  imitate  the  particular 
sounds  of  any  language. 

Imitation  is  seldom  an  exact  replica  of  the  act 
that  is  imitated.  The  imitator's  response  is  that 
habitual  act  of  his  that  most  nearly  resembles  the 
act  he  observes.  As  a  person  grows  older,  his  reac- 
tion tendencies  become  less  variable  and  more  stereo- 
typed. Thus  a  child  is  in  many  ways  a  better  mimic 
than  is  an  adult.  If,  for  example,  in  his  playing 
with  sounds,  a  baby  has  familiarized  himself  with  a 


LEARNING  133 

certain  French  vowel,  he  is  likely  to  imitate  it  with 
considerable  accuracy,  whereas  an  adult,  whose  lan- 
guage responses,  throughout  a  lifetime  of  practice, 
have  been  confined  to  English  sounds,  will  imitate 
the  French  vowel  by  its  nearest  approximation  in 
his  native  tongue. 

In  New  England  the  invocation,  "0  mihi  beate 
Marti/ne,"  is  found  in  degenerate  form  as  the  ex- 
clamation, "Oh  my  eyes  and  Betty  Martin."  The 
baseball  player  in  his  first  attempts  at  golf  imitates 
a  golf  stroke  inaccurately  because  of  his  familiarity 
with  a  bat.  One  of  the  reasons  that  it  is  hard  to 
learn  to  dive  is  because  we  have  learned  so  well  to 
jump  feet  foremost  The  motion  picture  actor's 
failure  to  imitate  the  behavior  of  a  social  class  to 
which  he  does  not  belong  is  the  product  of  a  life 
spent  in  acquiring  a  manner  of  quite  another  sort. 
The  plasticity  of  children  lies  in  their  relative  free- 
dom from  stereotyped  habits.  The  behavior  of  an 
adult  falls  into  ruts  from  which  he  extricates  him- 
self only  with  great  difficulty. 


CHAPTER  IV 


COENOTROPES 


Watson  performed  an  experiment  in  which  a 
baby  was  shown  a  white  rat.  The  baby  looked  at 
the  rat  without  displaying  any  fear.  The  rat  was 
exhibited  again,  and,  while  the  baby  was  looking  at 
it,  an  iron  bar  was  struck.  The  resulting  noise 
caused  the  characteristic  and  instinctive  fear  re- 
sponse. When  the  rat  was  exhibited  a  third  time, 
the  sight  of  the  animal  called  out  the  fear  reaction. 
In  this  way  the  experimenter  secured  a  conditioned 
response  to  the  substituted  visual  stimulus.  The 
baby  had  become  afraid  of  rats.  In  similar  fash- 
ion, fear  could  be  attached  to  toy  balloons,  chrysan- 
themums, the  experimenter,  or  to  any  object  whose 
visual  appearance  had  originally  no  power  to  cause 
the  emotion  of  fear. 

No  movements,  except  eye  movements,  are  in- 
stinctively elicited  by  a  visual  stimulus.  The  baby 
is  surrounded  by  the  world  of  things  seen,  and  all 
these  visual  stimuli  are  available  for  substitution. 
By  conditioning,  the  sight  of  an  object  prompts  the 
baby  to  do  again  what  he  was  doing  when  he  saw 
the  object,  and  in  time  many  complicated  and  elabo- 
rate responses  are  determined  by  what  he  sees. 

The   avoidance   movements   of   fear,   the   attack 

134  * 


OOENOTROPES  135 

movements  of  rage,  and  the  approach  movements 
of  love  are  given  to  visual  stimuli  only  through 
the  process  of  conditioning.  We  must  learn  to  keep 
our  distance  from  charged  wires,  dangerous  ani- 
mals, stoves,  falling  objects,  and  people  who  sneeze. 
We  must  acquire  the  habit  of  striking  out  at  aggres- 
sors who  have  not  yet  touched  us,  and  to  cry  when 
dangerous  objects  are  seen  approaching.  Without 
previous  bodily  contact,  probably  no  sex  responses 
would  be  given  to  visual  stimuli. 

Babies  are  instinctively  afraid  of  thunder,  but 
not  of  lightning.  When  lightning  accompanies  the 
thunder,  it  takes  on  the  power  to  make  the  baby 
afraid.  Objects  acquire  frightfulness  by  being  pres- 
ent during  fear. 

Few  people  are  afraid  of  toy  balloons,  but  many 
are  afraid  of  the  sight  of  dogs.  This  is  because  few 
people  have  been  frightened  in  the  presence  of  a 
balloon,  but  many  have  been  barked  at  or  bitten 
while  looking  at  a  dog.  Where  loud  sounds  or  pain 
stimuli  are  naturally  inherent  in  a  situation,  the 
accompanying  stimuli  that  the  situation  offers  to 
eyes,  nose,  or  organs  of  touch  compel  in  all  men 
some  fear  as  a  conditioned  response.  Thus  there 
are  fears,  likes,  or  irritations  that  are  shared  by 
the  world  at  large.  But  this  is  usually  true  only 
when  the  situations  include  a  natural  stimulus, 
either  present  or  impending,  to  these  emotional  re- 
sponses. We  all  show  fear  when  confronted  with 
a  precipice  or  a  wild  cat,  although  this  is  not  an  in- 


136  GENERAL  PSYCHOLOGY 

stinctive  response.  We  share  with  our  fellows  an 
ideal  of  feminine  beauty,  which  is  a  matter  of  com- 
mon training.  Anyone  is  annoyed  when  he  sees  that 
he  has  missed  his  train,  although  the  sight  of  a  de- 
parting train  is  not  an  original  stimulus  for  anger. 

Equipped  with  fairly  definite  response  tendencies, 
a  baby  is  born  into  an  orderly  world.  He  is  exposed 
to  a  systematic  routine  and  a  fixed  sequence  of  situ- 
ations. Above  all,  the  combination  of  stimuli  resi- 
dent in  such  objects  as  his  bed,  his  clothing,  his 
tub,  his  mother,  and  his  own  body  is  almost  invari- 
able. The  original  nature  common  to  all  babies, 
together  with  the  inevitable  environment  they  all 
share,  develops  similar  habits  in  all  children.  That 
all  people  have  not  identical  habits  is  due  to  individ- 
ual differences  in  endowment  and  to  the  peculiar- 
ities of  the  world  that  each  lives  in.  These  neu- 
rological and  environmental  differences  are  more 
likely  to  be  noticed  than  the  commonality  of  endow- 
ment and  the  universality  of  the  world  order,  which 
latter  are  so  commonplace  that  their  importance  is 
often  underestimated. 

The  habits  that  are  produced  and  called  out  by 
common  situations  that  everyone  experiences,  are 
frequently  given  such  names  as  fighting  instinct, 
mating  instinct,  hunting  instinct,  hoarding  instinct, 
shelter-seeking  instinct,  maternal  instinct,  gregari- 
ous instinct,  or  instincts  of  curiosity,  approval, 
scorn,  mastery,  and  submission.  Even  in  the  be- 
havior of  lower  animals  the  acts  described  by  these 


COENOTROPES  137 

terms  may  owe  something  to  learning.  When  per- 
formed by  man,  they  are  always  acquired  reaction 
tendencies,  though  we  all  possess  them  by  virtue  of 
our  having  a  common  human  nature  that  is  trained 
in  a  common  world.  The  extent  of  man's  capacity 
for  forming  conditioned  responses,  which  distin- 
guishes him  from  lower  animals,  is  the  outstand- 
ing attribute  of  human  nature. 

Habits  that  men  universally  share  are  obviously 
to  be  distinguished  from  the  private  habits  of  type- 
writing, piano  playing,  vocations,  hobbies,  personal 
idiosyncrasies,  and  the  like.  There  is  no  adequate 
term  for  these  common  habits  in  psychology.  They 
might  be  called  instinct-habits,  common  action  pat- 
terns, vulgarities,  primary  acquirements,  or  com- 
mon acquisitions,  but  all  these  terms  are  either  am- 
biguous or  cumbersome  and  none  of  them  is  suffi- 
ciently concise  to  describe  so  important  a  class  of 
acts.  For  lack  of  a  better  word  we  shall  employ 
the  term  coenotropes  to  describe  common  modes  of 
learned  response  that  are  the  product  .of  original 
nature  and  commonly  shared  environment.1  Fur- 
ther experiment  may  discover  the  integration  of 
these  coenotropes  to  be  more  dependent  upon  the 
slow  maturation  of  innate  nervous  structures  than 
we  now  have  reason  to  suppose. 

A  group  of  learned  acts  may  be  given  a  common 
name  because  of  the  similarity  of  the  situations  that 

i  The  word  coenotrope,  pronounced  seenotrope,  Is  derived  from 
koiv6s  common,  and  rp6iro%  habit. 


138  GENERAL  PSYCHOLOGY 

cause  them  or  because  of  the  similarity  of  their  re- 
sults, and  thus  very  dissimilar  acts  may  be  classed 
together.  The  common  mode  of  behavior  known  as 
"collecting"  is  made  up  of  diverse  acts  whose  re- 
sults show  a  greater  resemblance  than  do  the  acts 
themselves.  Head  hunting  and  stamp  collecting  are 
very  different,  but  both  acts  result  in  possessing  a 
collection.  The  common  mode  of  behavior  known 
as  "curiosity"  may  be  illustrated  by  acts  so  dis- 
similar as  peeping  through  a  hole  in  a  high  board 
fence  and  buying  a  newspaper.  All  acts  of  curios- 
ity, however,  are  excited  by  situations  that  are  sim- 
ilar in  their  make-up,  so  that  the  situation  serves 
here  as  a  basis  for  classification. 

Such  a  class  name  as  "shaving"  denotes  a  specific 
act  that  is  a  part  of  the  learned  equipment  of  many 
individuals.  The  characteristic  use  of  many  objects, 
such  as  a  razor  or  an  umbrella,  constitutes  a  com- 
mon mode  of  behavior  that  is  not  made  up  of  diverse 
acts. 

Common  Habits 

The  original  tendencies  mentioned  in  the  chapter 
on  "Instinct"  are  fairly  simple  responses.  It  is 
possible  that  there  are  more  elaborate  acts  that 
properly  may  be  considered  a  part  of  original  human 
nature. 

A  baby,  however,  may  acquire  conditioned  re- 
sponses immediately  after  birth,  and  the  older  ob- 
servers did  not  distinguish  carefully  between  habit 


COENOTROPES  139 

and  instinct  in  reporting  the  behavior  of  babies. 
As  any  normal  child  grows  older  we  find  him  creep- 
ing, walking,  balancing  without  support  and  with 
stationary  feet,  climbing,  hitting,  throwing,  running 
in  pursuit  of  moving  objects,  avoiding  obstacles  in 
his  path,  and  making  many  other  movements  that 
the  young  of  lower  animals  make  as  a  result  of  neu- 
rological endowment.  To  what  extent  these  acts  in 
the  human  child  are  instinctive  is  largely  a  matter 
of  surmise.  The  child's  opportunity  for  establish- 
ing many  of  these  stereotyped  responses  by  trial 
and  error  learning  is  certainly  great,  and  the  uni- 
formity of  conditions  under  which  all  children  live 
makes  tenable  the  assumption  that  learning  is  here 
an  important  factor. 

Spalding  demonstrated  that  birds  fly  without  pre- 
liminary trials,  and  that  their  awkward  first  at- 
tempts at  flying  are  due  to  the  immature  condition 
of  an  instinctive  flying  mechanism.  His  experiment 
was  to  confine  one  set  of  birds  so  that  they  could  not 
fly  and  to  leave  unrestrained  a  control  group  of  the 
same  age.  When  the  control  group  had  "learned" 
to  fly  successfully,  the  confined  birds  were  liberated 
and  were  found  to  fly  at  once  with  all  the  precision 
of  the  others.2 

It  would  be  unjustified  to  infer  by  analogy  that 
the  child's  first  blundering  efforts  at  walking  are 
similarly  the  responses  of  an  immature  walking 
mechanism.     It  has  been  pointed  out  already  that 

2  Preyer,  Mind  of  the  Child,  Part  1,  p.  239;  Spalding,  in  Nature, 
vol.  12,  p.  507. 


140  GENERAL  PSYCHOLOGY 

man  lacks  in  large  part  the  elaborate  instinctive 
tendencies  of  the  lower  animals.  Spalding's  results, 
however,  should  make  us  cautious  of  denying  in  the 
case  of  the  baby  a  natural  ability  to  walk.  There 
is  some  evidence  that  this  ability  is  a  chain  reflex. 
Spontaneous  walking  without  preliminary  trials  has 
been  occasionally  reported  of  babies  under  the  ob- 
servation of  psychologists. 

Balancing  on  the  feet  is  almost  certainly  an  in- 
stinctive endowment,  just  as  is  balancing  the  head. 
Stair  climbing,  and  many  other  forms  of  locomotion 
involving  the  surmounting  of  obstacles,  are  in  part 
habits. 

In  the  absence  of  experimental  work  we  must  be 
content  with  conjecture  as  to  how  a  child  learns  to 
throw.  Grasping  and  releasing  an  object  are  in- 
stinctive, as  are  also  patting  movements  of  the  arms. 
The  combination  of  these  movements  may  result  in 
throwing  any  object  that  is  held  in  the  hand.  The 
serial  response  so  established  by  trial  and  error 
may  be  the  beginning  of  a  throwing  habit.  Skillful 
manipulation  of  objects  and  the  stereotyped  move- 
ments involved  in  transporting  objects  from  place 
to  place  can  not  be  regarded  as  instinctive. 

More  than  95  per  cent  of  adults  are  right-handed. 
It  may  be  asked  whether  this  is  an  acquisition  or  a 
natural  tendency.  Most  children  are  trained  by  their 
parents  to  use  the  right  hand  in  holding  and  manipu- 
lating such  articles  as  cups,  spoons,  or  pencils.  Doll 
reports  that  among  the  feeble-minded   about  half 


COENOTROPES  141 

are  right-handed  and  half  are  left-handed.3  This, 
together  with  the  facts  that  the  feeble-minded  are 
characteristically  apathetic  toward  instruction  and 
that  they  often  occur  in  families  where  but  little 
instruction  is  offered,  suggests  the  possibility  that 
dextrality  is  the  result  of  training.  Among  babies 
up  to  the  age  of  three  weeks  Watson  found  no  pref- 
erential use  of  either  hand  in  supporting  the  body 
weight. 

The  absence  of  any  isolated  society  of  left-handed 
people  opposes  the  hypothesis  that  right-handedness 
is  wholly  an  acquisition.  In  anthropological  mu- 
seums a  left-hand  weapon  is  an  anomaly,  although 
the  Australian  boomerang  is  usually  thrown  with 
the  left  hand.  There  is  some  evidence  for  the  be- 
lief that  among  left-handed  persons  the  regions  of 
Broca  and  Wernicke  are,  contrary  to  the  rule,  com- 
monly found  in  the  right  hemisphere.  If  this  is  so, 
it  might  argue  for  an  instinctive  right-  or  left-hand- 
edness. 

Original  responses  of  spitting  out,  grimacing,  and 
head-turning  seem  to  follow  gustatory  stimulation 
by  bitter  and  sour  substances.  When  sugar  solu- 
tion is  placed  on  the  lips,  sucking  and  licking  result. 
Refusal  to  nurse  when  the  nipple  has  been  smeared 
with  oil  of  amber  or  petroleum  is  reported  by  Kro- 
ner.4   It  is  doubtful  whether  this  is  a  tactile  or  an 

3  Doll,  "Anthropometry  as  an  Aid  to  Mental  Diagnosis,"  Research 
Publication  8,  Training  School,  Vineland,  New  Jersey,  1916. 

•*  Peterson  and  Rainey,  "Beginnings  of  Mind  in  the  New  Born," 
in  the  Bulletin  of  the  Lying-in  Hospital  of  the  City  of  New  York, 
1910. 


142  GENERAL  PSYCHOLOGY 

odor  response.  Peterson  and  Rainey  attribute 
grimacing,  sucking  movements,  and  restlessness  to 
olfactory  stimulation. 

Natural  tendencies  of  approach  and  of  avoidance 
are  thus  organized  about  situations  of  direct  vital 
importance.  Avoidance  responses  are  provoked  by 
noxious  stimuli  and  by  stimuli  that  are  distinctively 
characteristic  of  harmful  situations.  Instinctive  re- 
actions to  restraint,  loud  noises,  and  bodily  injury 
have  already  been  described.  Approach  or  quies- 
cence is  called  out  by  stimuli  that  are  commonly  as- 
sociated with  the  presence  of  food  or  with  safe  and 
beneficial  conditions.  This  ambivalent  equipment 
gives  direction  to  all  habit  formation,  and  with  it 
the  new-born  infant  is  ready  to  enter  upon  trial  and 
error  learning  with  considerable  security.  No  visual 
stimulus,  unless  intense  enough  to  cause  injury,  will 
elicit  original  movements  of  avoidance  or  attack.  A 
baby  soon  learns,  however,  to  retreat,  struggle,  or 
cry  at  sight  of  those  objects  whose  contact  has  on 
previous  occasions  aroused  avoidance.  Conditioned 
responses  of  this  sort  soon  modify  the  baby's  origi- 
nal nature. 

When  instinctive  avoidance  is  unsuccessful  in 
freeing  the  child  from  noxious  stimuli,  movements, 
of  attack  are  generally  the  instinctive  result.  Thus 
resistance  to  the  intention  of  others  is  early  de- 
veloped and  bad  temper  follows  upon  teasing  or 
upon  the  rough  handling  sometimes  involved  in 
dressing,  bathing,  or  in  any  abrupt  manipulation. 


COENOTROPES  143 

The  attainment  of  coenotropes  and  of  instinctive 
chain  reflexes  does  not  occur  until  some  time  after 
birth.  If  a  ten-day  old  chick  has  never  seen  a  hen, 
it  will  not  follow  a  hen.  James  argues  from  this, 
and  from  similar  examples,  that  "many  instincts 
ripen  at  a  certain  age  and  then  fade  away. ' ' 5  He 
cites  Spalding's  account  of  a  chick  that  was  kept 
away  from  its  mother  for  the  first  ten  days  and 
then,  being  replaced,  showed  no  tendency  to  follow. 
It  did,  however,  follow  any  person  of  whom  it  caught 
sight,  having  acquired  this  habit  during  the  first 
few  days. 

This  fact  should  not  be  interpreted  to  mean  that 
an  instinct  had  faded  away.  There  is,  of  course, 
no  following-the-hen  instinct.  The  young  chick  will 
follow  anything,  a  handkerchief  dragged  along  the 
floor,  or  a  retreating  man,  dog,  or  hen.  The  young 
and  inexperienced  chick  follows  either  man  or  hen 
to  the  disregard  of  stationary  objects.  The  original 
tendency  to  follow  is  probably  stronger  than  the  orig- 
inal tendency  to  approach  anything  that  is  at  rest. 
If  the  threshold  for  following  a  man  has  been  low- 
ered by  practice,  even  though  the  tendency  to  ap- 
proach the  still  object  is  similarly  lowered,  man- 
following  may  prevail  over  the  tendency  to  approach 
the  motionless  object.  As  no  practice  has  lowered 
the  threshold  of  the  hen-following  response,  the 
chick  may  well  disregard  the  hen  and  busy  itself 

s  James,  Principles  of  Psychology,  vol.  ii  p.  398. 


144  GENERAL  PSYCHOLOGY 

with  other  stimuli,  the  responses  to  which  have  been 
well  practised. 

The  response  tendencies  present  in  the  new-born, 
being  uninhibited  by  incompatible  habits,  may  be- 
come attached  to  any  one  of  a  multitude  of  objects. 
Distracting  habits  once  formed,  however,  inhibit  the 
relatively  sluggish  instinctive  response  to  a  novel 
object,  although  this  response  might  have  been 
given  before  such  incompatible  habits  stood  in  the 
way. 

The  oft  rehearsed  man-following  habit  of  Spald- 
ing's chick  was  well  enough  grounded  to  compete 
successfully  with  the  tendencies  to  scratch,  peck,  or 
make  off  toward  moving  bugs.  There  being  no  hen- 
following  habit,  we  may  suppose  that  the  hen,  when 
later  introduced,  was  merely  powerless  to  compete 
for  the  chick's  attention  in  the  face  of  these  distrac- 
tions. This  seems  more  reasonable  than  the  hy- 
pothesis of  transiency  of  instinct. 

As  with  the  chick,  so  with  the  child.  At  first  one 
wet-nurse  will  be  accepted  about  as  readily  as  an- 
other, but  later,  when  the  infant  has  formed  the 
nursing  habit  toward  his  mother,  she  alone  is  able 
to  elicit  energetic  and  contented  suckling.  Some- 
thing in  his  mouth  is  not  the  only  stimulus  that  calls 
forth  the  nursing  response  in  the  practised  baby. 
His  mother's  way  of  holding  and  talking  to  him, 
the  shape  of  her  breast  and  her  general  appearance 
are  all  conditioning  stimuli  that  facilitate  the  child's 
nursing.    In  the  case  of  the  strange  nurse,  the  ab- 


COENOTROPES  145 

sence  of  these  conditioning  stimuli  permits  the  suc- 
cess of  rival  movements  of  resistance  and  crying 
that  tend  to  follow  manipulation.  Such  movements 
are  inhibited  by  the  behavior  called  out  by  the 
mother.  Once  the  movements  of  resistance  and  cry- 
ing have  been  elicited  by  the  strange  nurse,  the 
characteristics  in  which  she  differs  from  the  mother 
may  condition  these  movements,  so  that  the  baby 
will  struggle  in  her  arms  the  next  time,  unless  she 
has  succeeded  in  getting  him  to  nurse  on  the  first 
occasion.  We  have  no  ground  for  supposing  that 
mere  strangeness  causes  resistance,  except  in  so  far 
as  a  strange  situation  may  have  the  effect  of  break- 
ing up  an  habitual  response  series. 

Instincts  ripen  but  do  they  fade?  With  his  law 
of  transiency  of  instinct  in  mind,  James  says, 
"There  is  a  happy  moment  for  fixing  skill  in  draw- 
ing, for  making  boys  collectors  in  natural  history, 
and  presently  dissectors  and  botanists;  then  for 
initiating  them  into  the  harmonies  of  mechanics  and 
the  wonders  of  physical  and  chemical  law."  There 
is  certainly  a  " happy  moment"  for  teaching  a  child 
any  habit.  This,  however,  is  probably  not  a  "nas- 
cont  period"  but  rather  a  time  before  antagonistic, 
incompatible,  or  distracting  habits  have  been  formed. 

Both  Instincts  and  Coenotropes  Are  Common 
Modes  of  Behavior 

An  uncritical  description  of  instinct  as  the  be- 
havior that  is  common  to  all  men  was  popularized 


146  GENERAL  PSYCHOLOGY 

by  the  contemporaries  of  Darwin.  Although  all  men 
are  fundamentally  alike  in  their  original  structure, 
there  are  individual  differences  in  instinctive  en- 
dowment, and  this  individuality  is  no  less  instinctive 
than  commonality  or  universally  shared  traits. 
Furthermore,  a  great  deal  of  the  behavior  that  is 
common  to  all  men  is  undoubtedly  learned.  Every- 
body knows  how  to  use  a  stick  as  a  weapon,  but  no 
one  does  so  instinctively.  Wearing  clothing  is  as 
universal  as  many  of  the  elaborate  instincts  of  lower 
animals,  but  is,  of  course,  a  learned  act.  The  be- 
havior that  is  characteristic  of  any  particular  cul- 
ture, and  that  is  not  found  elsewhere,  can  not  be  at- 
tributed to  original  structure,  but  should  be  re- 
garded as  the  effect  of  environment. 

The  nest  building  of  birds  and  insects,  the  web 
building  of  spiders,  and  the  cocoon  spinning  of  lar- 
vae are  striking  examples  of  complicated  and  elabo- 
rate instincts.  These  acts  may  be  futile  if  the  nor- 
mal course  of  events  is  interfered  with,  but  the 
lower  animals  are  not  deterred  by  minor  irregulari- 
ties of  situation.  Elaborate  and  serially  combined 
responses  are  characteristic  of  their  instinctive  be- 
havior. On  the  other  hand,  the  instinctive  acts  of 
man  are  relatively  simple,  but  in  the  process  of 
learning,  these  simple  responses  take  on  many  and 
varied  combinations.  The  more  we  investigate  man's 
original  nature  the  less  intricate  his  instinctive  re- 
actions appear  to  be.  We  ought  probably  to  re- 
gard the  elaborate  instincts  attributed  to  man  by 


OOENOTROPES  147 

the  school  of  William  James  as  being  for  the  most 
part  learned  acts. 

To  call  pugnacity,  or  constructiveness,  or  acqui- 
sitiveness, or  self-preservation,  or  mating,  an  in- 
stinct is  a  dangerous  concession  to  popular  usage. 
Each  component  act  as  elicited  by  a  particular  situa- 
tion might  better  be  so  called,  always  bearing  in 
mind  that  this  series  of  acts  is  terminated  by  a  con- 
summatory  response.  A  complete  understanding 
of  behavior  always  involves  an  analysis  in  terms 
of  stimulus-response  mechanisms,  and  to  name,  for 
example,  all  the  behavior  of  carnivorous  animals 
that  results  in  securing  food  "the"  hunting  instinct 
serves  little  purpose  but  to  end  prematurely  the 
student's  scientific  curiosity.  If  we  rest  content 
with  the  description  of  the  hunting  instinct  as  the 
unlearned  behavior  of  a  carnivorous  animal  that 
results  in  his  securing  food,  we  certainly  add  noth- 
ing to  anyone's  information  when  we  say  that  ani- 
mals secure  food  by  means  of  the  hunting  instinct. 
Such  an  explanation  is  of  the  sort  given  by  Mo- 
liere's  physician  when  he  says  that  opium  puts  one 
to  sleep  because  it  possesses  a  soporific  property. 
If  we  are  going  to  make  use  of  "instinct"  in  the 
description  of  behavior,  the  terms  must  apply  to 
specific  reaction  tendencies. 


148  GENERAL  PSYCHOLOGY 

Play 

One  of  the  most  conspicuous  instances  of  the 
unconsidered  explanation  of  conduct  in  terms  of  a 
so-called  instinctive  tendency  is  the  popular  ex- 
planation of  play.  For  a  century  past  many  writers 
have  accounted  for  the  whole  range  of  play  activ- 
ities in  terms  of  a  general  "play  impulse,"  or  "in- 
stinct to  play,"  or  "a  disinclination  to  remain  un- 
occupied." This  resembles  the  attempted  explana- 
tion of  acts  so  various  as  a  snowball  contest  and 
the  writing  of  a  hostile  editorial  as  manifestations 
of  an  "instinct  of  pugnacity. " 

A  short  examination  of  play  will  serve  to  illus- 
trate the  method  of  analysis  of  all  coenotropic  ten- 
dencies. When  this  has  been  done,  the  student  will 
be  less  likely  to  consider  pugnacity,  curiosity,  or 
piety  as  simple  instincts.  He  should  then  not  rest 
satisfied  when  told  that  men  fight  because  of  a  com- 
bative instinct,  that  they  investigate  because  of 
instinctive  curiosity,  or  that  they  are  religious  be- 
cause of  an  innate  religiosity. 

Compared  with  practical  conduct,  play  is  an  in- 
complete act  given  in  response  to  an  incomplete 
situation.  It  will  be  remembered  that  a  situation 
is  made  up  of  many  stimuli  and  that  an  act  is  com- 
posed of  many  combined  responses.  The  situations 
to  which  the  young  are  exposed  are  almost  always 
lacking  in  stimuli  that  are  present  in  the  situations 


OOENOTROPES  149 

that  confront  the  adult.  The  puppy's  antagonist 
does  not  tear  the  puppy's  flesh,  and  is  otherwise 
less  aggressive  than  the  opponent  of  the  large  dog. 
The  child's  doll-house  lacks  stairways,  plumbing, 
and  many  of  the  necessary  parts  of  a  real  house.  The 
doll  itself  may  be  so  elaborated  as  to  close  its  eyes 
or  squeak,  but  it  is  grossly  lacking  in  the  character- 
istics of  a  real  baby.  You  sit  down  on  the  rug  and 
say,  "Let's  play  that  this  is  a  boat."  For  play 
purposes  the  absence  of  naval  architecture  is  as  un- 
important as  the  absence  of  surrounding  water. 
The  next  door  neighbor  is  an  Indian  if  he  has  feath- 
ers and  a  tomahawk,  even  though  he  lacks  the  blood- 
thirstiness  of  the  actual  redskin. 

Just  as  the  play  situations  are  limited,  so  are  the 
acts  of  play  correspondingly  limited.  The  puppy 
is  actuated  to  gentle  aggression  and  limited  retreat, 
whereas  a  richer  situation  with  more  intense  stimuli 
would  have  resulted  in  either  real  fighting  or  flight. 
The  child's  doll-housekeeping  is  very  sketchy,  and 
her  care  of  the  doll  is  thoroughgoing  only  in  such 
matters  as  hugging  and  spanking.  The  child's  skill 
in  handling  the  rug-boat  would  never  qualify  him  as 
a  real  navigator.  His  assault  upon  the  Indian  next 
door  is  fortunately  abortive,  and  may  even  be  lim- 
ited to  saying  the  word  "bang." 

"We  are  apt  to  say  that  the  child  fills  in  the  gaps 
in  the  situation  by  imagination.  This  is  often  an 
unjustified  interpretation  by  the  adult,  who  is  more 
likely  than  the  child  to  notice  the  gaps  and  to  inter- 


150  GENERAL  PSYCHOLOGY 

pret  the  fairy  story  or  to  people  the  mud  pie  with 
apples. 

Not  only  is  the  local  situation  incomplete,  but 
there  is  an  incomplete  apprehension  of  the  larger 
situation.  The  cues  to  distant  but  related  situations 
that  occur  in  the  limited  play  environment  are  over- 
looked. For  this  reason  play  is  characterized  by 
the  low  stimulus  thresholds  that  are  present  within 
the  smaller  situation  and  that  are  due  to  the  absence 
of  inhibiting  and  facilitating  effects  of  more  distant 
situations.  There  is  involved  a  disregard  of  incon- 
gruities, as  in  the  theater  when  the  background  is  a 
canvas  drop  instead  of  a  prison  wall,  and  when  the 
orchestra  pit  would  offer  a  way  of  easy  escape  for  a 
real  prisoner.  Children  at  play  have  a  high 
threshold  for  the  summons  of  parents  but  a  very  low 
one  for  the  behavior  of  their  playmates.  Thus  play 
situations  are  more  or  less  isolated  from  the  world 
as  a  whole.  The  player  is  detached,  irresponsible, 
carefree.  Although  this  same  isolation  may  at  times 
seem  to  characterize  serious  work  as  well,  this  is 
really  never  so,  work  always  being  controlled  by  re- 
mote situations  more  or  less  suggested  by  present 
stimuli.  Freedom  from  this  kind  of  facilitating  and 
inhibiting  stimuli  accounts  for  the  frequent  descrip- 
tion of  play  as  activity  without  external  compul- 
sion, or  as  aimless  or  purposeless  activity.  Such  a 
description  tacitly  assumes  that  work  requires  re- 
enforcement  from  associated  situations. 

In  the  nature  of  things  children  play  more  than 


COENOTROPES  151 

do  adults.  If  they  react  at  all  to  a  limited  environ- 
ment, it  must  be  with  a  limited  response.  Play,  how- 
ever, is  not  lacking  in  adult  behavior.  It  is,  of 
course,  often  deliberately  planned.  In  athletic  con- 
tests and  games,  conventional  restrictions  inhibit 
certain  of  the  responses  of  participants,  and  so  limit 
the  situation  to  which  the  others  respond.  On  the 
track  we  are  not  tripped  up  or  pushed,  although  un- 
der more  grim  conditions  this  would  be  a  part  of  the 
situation.  Our  opponent  at  tennis  does  not  attack 
us  with  his  racquet  and  our  boxing  partner  attacks 
us  only  with  his  gloves. 

Not  only  is  an  act  of  play  incomplete  when  com- 
pared with  the  movements  involved  in  serious  work, 
but  the  play  act  contains  many  movements  not  found 
in  practical  life.  Probably  the  most  conspicuous  of 
these  superfluous  play  movements  is  the  talking 
that  is  nearly  always  a  part  of  make-believe  be- 
havior. In  playing  " horse"  with  a  broomstick  a 
child  will  speak  to  the  object  in  a  way  that  would  be 
useless  if  the  plaything  were  real.  He  will  explain 
to  the  onlookers  intaginary  characteristics  of  his 
mount.  Moreover  he  substitutes  his  own  locomo- 
tion for  that  of  the  supposititious  animal.  The 
horse's  life  is  crowded  with  a  wealth  of  dramatic  in- 
cident that  no  actual  horse  would  tolerate. 

The  origin  of  the  extra  movements  of  play  is  to 
be  looked  for  first  in  the  necessity  the  child  faces  of 
compensating  for  the  sketchiness  of  his  playthings. 
If  the  horse  is  unable  to  pull  the  child,  the  child 


152  GENEKAL  PSYCHOLOGY 

must  pull  the  horse.  The  absence  of  temper  in  the 
wooden  animal  is  made  up  for  by  much  jerking, 
shaking,  and  clinging  on  the  part  of  the  rider. 
Other  sources  of  superfluous  movement  are  emo- 
tional expression,  the  traditional  way  of  playing 
such  and  such  a  game,  and  the  habits  the  child  has 
formed  in  somewhat  similar  situations. 

Just  as  play  acts  contain  superfluous  movements, 
so  the  play  situations  contain  many  elements  not 
found  in  the  practical  world.  This  is  so  because  the 
child  is  obliged  to  use  make-shift  toys  and  to  look 
for  adventure  under  restricting  circumstances. 
The  tail  of  the  broomstick  horse  is  made  of  straw. 
Its  travels  carry  it  over  rugs,  through  hallways,  and 
up  the  stairs.  Its  existence  is  spent  in  an  incongru- 
ous world  and  may  at  any  time  come  to  an  end  when 
sweeping  begins. 

In  play  consummatory  responses  are  never  suc- 
cessfully expressed.  Tea  is  drunk  from  empty  cups. 
The  slaughtered  enemy  is  soon  back  in  the  fight. 
Kissing  games  are  supervised  by  adult  chaperones. 
In  short,  play  is  the  prolongation  of  preparatory  re- 
sponses, the  consummatory  response  never  being 
sufficiently  complete  to  terminate  the  behavior.  Par- 
tial responses  to  incomplete  sex  situations  occur 
from  earliest  infancy.  Before  the  baby  is  able  to 
carry  on  a  successful  fight  he  shows  anger,  and 
fear  is  manifest  before  he  has  developed  the  move- 
ments necessary  to  flight.  The  incompleteness  of 
consummatory  responses  in  play  maintains  the  pre- 


COENOTROPES  153 

current  responses  and  produces  a  high  pitch  of  emo- 
tional excitement. 

The  energy  with  which  play  activities  are  carried 
on  suggests  at  once  their  reenforcement  from  inter- 
nal responses  such  as  are  present  in  the  preparatory 
acts  of  hunger,  love,  rage,  and  fear.  With  the  be- 
ginning of  play  any  lassitude  that  may  have  been 
evident  disappears.  In  dancing,  boxing,  and  the 
game  of  hide-and-seek  the  complete  response  is 
aborted.  With  the  proper  additions  to  the  situa- 
tions the  excitement  of  play  may  be  increased  to 
the  point  of  actual  love,  rage,  or  fear. 

It  follows  from  what  has  been  said  that  play  can 
not  be  described  as  a  specific  instinct,  nor  is  there 
any  group  of  original  response  tendencies  that  in 
themselves  constitute  play.  Play  is  almost  as  much 
dependent  on  learning,  the  fixation  of  habits,  and 
the  organization  of  responses  aoout  objects  and 
situations  as  are  the  serious  activities  of  adult  life. 

Other  Examples  of  Common  Modes  of  Behavior 

It  is  not  practicable  to  undertake  a  discussion  of 
all  coenotropes  because  of  their  great  number,  and 
because  many  of  them  are  relatively  unimportant. 
The  student  must  acquire  the  ability  to  analyze  the 
many  common  modes  of  action  that  have  class  names 
in  common  speech,  and  to  distinguish  the  parts 
played  by  original  nature  and  by  learning.  Fear 
of  strangers,  homesickness,  fear  of  the  dark,  and 


154  GENERAL  PSYCHOLOGY 

curiosity  will  serve  as  representatives  of  the  many 
coenotropes  that  are  ordinarily  recognized. 

No  baby  shows  a  fear  of  strangers  until  he  has 
developed  many  habitual  responses  toward  his  fam- 
ily. These  habitual  responses  are  called  out  in 
fairly  definite  order  by  such  stimuli  as  his  mother's 
appearance  and  the  way  in  which  she  acts.  He 
comes  to  adjust  his  responses  to  his  mother's  next 
move,  and  if  she  behaves  in  an  unusual  way,  his 
serial  response  is  disrupted,  with  the  result  that  he 
is  likely  to  cry.  Since  the  performance  of  any  serial 
habit  response  depends  upon  receiving  the  proper 
stimulus  for  each  step  in  the  series,  the  absence  of 
any  one  of  these  usual  stimuli,  or  the  presence  of 
any  stimulus  provoking  an  incompatible  response, 
will  result  in  blocking  the  serial  reaction.  The 
blocking  of  any  habit  series  results  in  emotional 
arousal. 

When  a  stranger  holds  out  his  arms  to  a  baby,  the 
baby  may  respond  to  this  familiar  situation  by  ' '  go- 
ing" to  the  stranger.  Further  intercourse  with  the 
stranger,  however,  does  not  yield  those  stimuli  on 
which  the  baby's  intercourse  with  his  mother  is 
based.  His  chain  responses  are  thus  disrupted  and 
he  cries.  If  his  mother  is  standing  by,  the  sight 
of  her  will  cause  him  to  reach  out  toward  her  and 
thus  be  taken  from  the  stranger's  arms.  If  the 
stranger  wears  unfamiliar  glasses,  beard,  or  cloth- 
ing, other  strangers  of  like  appearance  will  be 
feared  when  met.    If  the  mother  is  by  custom  more 


COENOTROPES  155 

polite  to  strangers  than  she  is  to  members  of  her 
immediate  family,  her  manner  toward  guests  may 
become  the  cue  to  shyness  in  the  child. 

Homesickness  is  similarly  the  result  of  the  dis- 
rupting of  serial  response  tendencies  caused  by  the 
absence  of  necessary  and  familiar  stimuli.  The 
child  in  a  strange  situation  is  prompted  to  begin 
many  acts  that  can  not  be  carried  out.  Anyone  is 
ill  at  ease  when  his  habits  do  not  run  smoothly.  In 
a  foreign  country  his  speech  fails  to  alter  his  en- 
vironment in  the  way  that  is  compatible  with  his 
habits,  and  homesickness  results.  A  letter  from 
home  starts  behavior  that  can  not  be  consummated 
in  strange  surroundings,  and  he  shows  depression. 
People  whose  routine  involves  the  presence  of  others 
are  subject  to  loneliness  when  in  solitude. 

Darkness  is  not  an  original  stimulus  to  fear,  but 
there  are  many  factors  that  contribute  toward  the 
commonality  of  fear  of  darkness.  One  of  these  fac- 
tors is  the  disruption  of  responses  dependent  upon 
visual  stimuli.  Our  progress  across  the  room  is 
ordinarily  determined  by  what  we  see.  In  the  dark, 
the  serial  response  is  disorganized.  Moreover,  pre- 
vious injuries  from  violent  contact  with  objects  in 
a  dark  room  have  left  us  with  conditioned  responses 
of  avoidance  and  grief  to  darkness  as  a  substituted 
stimulus.  The  likelihood  of  fear  is  further  increased 
by  the  fact  that  when  the  light  is  turned  out,  we 
are  no  longer  distracted  by  what  we  see,  and  there 
is  less  interference  with  the   instinctive  tendency 


156  GENERAL  PSYCHOLOGY 

to  be  frightened  at  the  many  sounds  that  are  every- 
where present.  To  these  direct  causes  for  the  de- 
velopment of  a  common  fear  of  darkness  is  added 
the  observed  effect  of  darkness  upon  our  fellows. 

Curiosity  is  not  a  specific  act,  but  acts  of  curios- 
ity may  be  distinguished  as  a  class.  All  such  acts 
are  the  result  of  a  blocking  of  responses  that  are 
called  out  by  partly  unfamiliar  situations,  and  such 
behavior  is  always  accompanied  by  emotional  drive. 
Our  tendency  to  enter  the  dark  cave  is  blocked  by 
fear  of  the  wild  animal  that  might  inhabit  it.  If 
the  interior  of  the  cave  is  familiar  to  us,  we  feel 
no  curiosity.  Conversely,  no  unfamiliar  object 
arouses  curiosity  unless  some  element  of  the  situa- 
tion hinders  further  acquaintance.  Zest  is  added 
to  the  performance  of  any  act  by  reason  of  its  be- 
ing prohibited.  The  scientific  curiosity  of  a  gen- 
eration ago  concerning  biology  was  in  part  brought 
about  by  the  condemnation  of  the  theory  of  evolu- 
tion. Sex  curiosity  is  much  enhanced  by  social 
taboo.  The  emotional  drive  present  in  curiosity  is 
often  the  ordinary  accompaniment  of  the  act  that  is 
blocked,  but  is  always  augmented  by  the  difficulty 
of  carrying  out  the  act.  Fear,  love,  anger,  or  vari- 
ous mixtures  of  exciting  emotion  may  always  be 
recognized  in  curiosity.  The  classification  of  acts 
as  instances  of  curiosity  is  based  upon  the  presence 
of  this  emotional  drive,  upon  the  hindrance  in  the 
face  of  which  the  act  must  be  carried  out,  and  upon 
the  novelty  of  the  situation  receiving  attention.    Ex- 


COENOTROPES  157 

cept  in  this  setting,  no  specific  act  is  an  example  of 
curiosity. 

No  matter  how  much  man  modifies  his  conditions 
of  life,  the  human  nature  of  babies  remains  the  same ; 
and  though  man  may  build  up  elaborate  machinery 
of  law  and  custom  for  controlling  his  natural  ten- 
dencies, in  the  race  these  original  tendencies  remain 
the  constant  and  fundamental  determiners  of  be- 
havior. 


CHAPTER  V 


PERCEPTION 


A  single  object,  such  as  a  banana,  may  furnish 
stimuli  to  eyes,  ears,  nose,  tongue,  skin,  muscles,  or 
to  sense  organs  in  the  enteric  tract,  but  not  all  these 
stimuli  affect  us  at  the  same  time. 

A  watch  lies  on  the  table.  On  receiving  visual 
stimuli  from  a  portion  of  the  surface  of  the  watch, 
we  may  pick  it  up  and  receive  cutaneous  and  kin- 
aesthetic  stimuli,  turn  it  over  and  see  the  other  side, 
or  carry  it  to  the  ear  and  hear  it  tick.  It  is  in  the 
nature  of  objects  that  they  embody  this  assemblage 
of  diverse  stimuli. 

In  the  beginning,  our  responses  to  watches  or  to 
bananas  are  merely  reflexes  to  the  separate  stimuli 
those  objects  furnish.  While  we  respond  to  con- 
tact with  the  object,  other  stimuli  from  the  same  ob- 
ject frequently  act  upon  us.  While  seeing  an  ob- 
ject, we  may  also  smell  it.  While  smelling  it,  we 
may  also  hear  it.  Thus,  each  stimulus  may  finally 
call  forth,  by  conditioning,  any  of  the  responses 
that  any  of  the  other  stimuli  would  naturally  pro- 
voke. In  this  sense  we  may  say  that  an  adult  re- 
sponds to  an  object  as  a  whole.  After  experiencing 
together  the  various  stimuli  emanating  from  an  ob- 

158 


PERCEPTION  159 

ject,  we  react  in  a  way  that  anticipates  stimuli  that 
the  object  is  likely  soon  to  furnish. 

A  baby  finally  learns  to  avoid  bodily  contact  with 
fire,  barking  dogs,  whirling  machinery,  and  wet  paint 
merely  upon  seeing  them  at  a  distance,  although  the 
visual  appearance  of  these  objects  calls  forth  no 
original  avoidance  responses.  He  learns  to  smile 
at  sight  of  his  mother  who  has  cuddled  him,  to  cry 
at  the  touch  of  a  lifting  rod,  and  to  support  his 
nursing  bottle  with  his  two  hands  when  the  nipple 
is  placed  in  his  mouth.  All  these  acts  are  condi- 
tioned responses  to  substituted  stimuli,  and  the 
formation  of  such  conditioned  responses  constitutes 
acquaintance  with  the  objects. 

When,  by  this  process  of  conditioning,  any  stim- 
ulus from  the  object  furnishes  a  cue  for  the  early 
occurrence  of  responses  that  were  originally  given 
only  as  the  result  of  further  acquaintance,  the  baby 
is  said  to  perceive  the  object. 

It  is  in  the  process  of  manipulating  or  merely 
observing  a  thing  that  the  baby  receives  simultane- 
ously the  various  stimuli  that  are  resident  in  it. 
His  response  to  any  one  of  these  stimuli  may  then 
become  attached  to  any  other.  In  his  behavior  to- 
wards any  object  such  as  a  chair,  a  pin,  a  stick  of 
candy,  or  his  own  hand,  some  of  these  responses 
tend  to  become  dominant  and  are  attached  by  con- 
ditioning to  many  of  the  minor  stimuli  with  which 
the  object  provides  the  baby. 

Thus  objects  come  to  "look"  heavy,  hot,  smooth, 


160  GENERAL  PSYCHOLOGY 

wet,  or  soft.  Things  "sound"  large,  thin,  distant, 
or  as  though  in  rapid  motion.  By  touch  or  odor 
objects  may  be  identified. 

The  stimuli  offered  by  an  object  may  be  materially 
altered  as  a  result  of  the  baby's  intervention,  loco- 
motion, or  orientation.  If  he  tears  or  crumples 
paper,  it  makes  a  noise  and  takes  on  a  different 
visual  appearance.  If  he  grasps  a  pin,  it  may  prick 
his  finger.  If  he  inverts  the  inkstand,  the  ink  is 
spilled.  If  he  pushes  a  tumbler  off  the  table,  it 
falls  and  crashes.  If  he  releases  his  rattle,  it  may 
tumble  off  the  bed.  These  changes  in  the  form  or 
the  position  of  the  objects  occasion  new  responses, 
which,  by  conditioning,  are  later  called  out  by  any 
cue  the  object  furnishes. 

A  part  of  our  environment  is  always  changing. 
We  must  learn  to  look  out  for  danger  and  to  take 
advantage  of  fortunate  opportunities.  Moving  ob- 
jects alter  the  stimulation  they  give  us  although 
we  remain  quiet.  Animals,  guns,  matches,  and  en- 
gines have  their  own  peculiar  ways  of  behaving  in 
response  to  our  manipulations,  and  the  baby's  grow- 
ing perception  of  such  objects  as  these  includes 
many  anticipating  responses  dependent  on  past  en- 
counters. A  firecracker  never  looks  the  same  to  the 
baby  after  one  has  exploded  in  his  fingers.  The 
baby  ceases  to  use  the  cat's  tail  as  a  handle  after  he 
has  once  picked  up  an  aggressive  cat  in  this  way. 
He  learns  to  bounce  his  ball,  to  tease  his  parents, 
and  to  coerce  younger  children.    When  this  learn- 


PERCEPTION  161 

ing  has  occurred,  we  say  that  he  perceives  the  ball 
as  something  that  bounces,  parents  and  companions 
as  individuals  who  may  be  imposed  upon. 

Situations  recur  time  after  time  in  orderly  group- 
ing and  sequence.  The  frequent  reiteration  of  re- 
sponses to  these  recurring  events  enables  us  to  per- 
ceive a  situation  as  one  that  is  about  to  be  followed 
by  its  familiar  consequences.  Our  ability  to  do  this 
is  dependent  upon  the  overlapping  of  the  parts  of 
situations,  which  permits  the  formation  of  condi- 
tioned responses.  The  change  from  one  situation 
to  the  next  is  always  a  partial  change,  and  any  two 
successive  events  have  elements  in  common. 

There  is  then,  on  the  one  hand,  perception  of  ob- 
jects with  their  groupings  of  available  stimuli,  and, 
on  the  other  hand,  the  perception  of  events  with 
their  temporal  sequence  of  stimuli.  Perceptions  can 
not  be  sharply  divided  into  these  two  classes,  but 
any  perception  may  be  characterized  as  a  percep- 
tion chiefly  of  things  or  chiefly  of  occurrences. 

Perception  is  always  a  reaction  tendency  more 
or  less  completely  expressed.  When  less  complete, 
the  expression  is  often  limited  to  an  orientation  of 
receptors  and  effectors,  but  the  neurological  changes 
that  go  unobserved  are  often  far  reaching.  Thus  a 
perception  that  is  apparently  limited  to  orienta- 
tion may  be  a  very  extensive  process  in  the  central 
nervous  system.  As  a  result  of  our  observing  a 
thing,  the  thresholds  of  many  other  responses  are 
raised  or  lowered.    When  we  glance  at  the  articles 


162  GENERAL  PSYCHOLOGY 

in  a  shop  window  or  hear  it  said  that  the  bank  closes 
to-day  at  twelve  o'clock,  delayed  reactions  are  ini- 
tiated that  are  brought  to  pass  only  upon  further 
stimulation,  or  in  conjunction  with  other  responses 
not  yet  aroused.  In  this  way  reaction  tendencies  are 
altered  by  stimuli  that  are  merely  observed,  and  to 
which  at  the  time  we  give  no  overt  response.  We 
may  sit  inertly  on  the  shore  and  watch  people  swim- 
ming, and  it  may  seem  to  an  onlooker  that  but  few 
responses  are  involved  in  our  perception.  The  next 
day,  however,  we  bring  a  swimming  suit  to  the  beach 
and  it  is  then  evident  that  many  changes  occurred 
in  our  nervous  structure  as  a  result  of  the  situa- 
tion that,  when  operating,  was  only  "observed." 
An  immediate  overt  reaction  to  objects  is  much  less 
frequent  than  is  the  act  of  observation. 

Perception  and  Speech 

Perceptions  involving  a  verbal  response  consti- 
tute a  most  important  class,  and  such  responses 
often  serve  to  drain  much  of  the  energy  that  situa- 
tions arouse.  Our  interest  in  a  distant  object  is 
often  terminated  as  soon  as  we  are  able  to  name  it. 

The  expression  of  word  perceptions  is  usually  sub- 
vocal.  Verbal  symbols  serve  as  cues  for  many  sub- 
sequent acts.  An  object  named  is  often  an  object 
with  which  we  are  in  a  better  position  to  deal,  be- 
cause much  appropriate  behavior  is  attached  to 
words  by  conditioning.    Once  we  have  said  "Good- 


PERCEPTION  163 

by"  there  is  little  to  do  but  to  go  away.  Before 
we  call  a  man  a  thief  we  are  less  aggressive  in  our 
antagonism  toward  him  than  we  are  after  the  word 
has  been  used. 

The  subvocal  expression  of  word  response  ten- 
dencies is  an  essential  part  of  thinking.  Perception 
in  verbal  terms  initiates  new  word  reactions,  and 
by  the  series  of  word  responses  our  conduct  is 
guided. 

Such  subvocal  responses  consist  in  slight  contrac- 
tion of  muscles  which,  if  stimulation  were  more  in- 
tense or  inhibitions  were  absent,  would  result  in 
actual  speech.  We  may  often  see  fellow  passengers 
on  the  street-car  moving  their  lips  in  a  manner  ap- 
propriate to  the  words  they  are  reading,  and  we  can 
readily  observe  slight  movements  of  our  own  vocal 
apparatus  that  are  minimal  movements  of  speech, 
even  though  these  could  not  be  detected  by  others. 

Such  minimal  responses  are  not  confined  to  speech. 
Many  of  the  onlookers  at  a  boxing  contest  may  be 
seen  to  follow  the  contest  with  minimal  defense  and 
attack  movements,  and  in  the  theater  audience  there 
are  many  who  shrug  their  shoulders  with  the  heroine 
and  become  stern  when  the  villain  is  confronted  by 
the  hero.  These  movements  are  sometimes  mimetic, 
but  that  they  are  not  regularly  so  is  shown  by  the 
fact  that  they  often  anticipate  the  movement  of  the 
boxer  or  of  the  actor,  and  are  the  onlooker's  response 
to  the  antagonist's  threatened  blow  or  to  the  vil- 
lain's advances. 


164  GENERAL  PSYCHOLOGY 

These  minimal  movements  constitute  in  part  the 
perception  of  situations,  and,  since  they  themselves 
offer  proprioceptive  stimulation,  such  movements 
may  be  the  cues  for  further  responses.  The  clenched 
fist  as  well  as  the  muttered  epithet  plays  a  part  in 
determining  subsequent  action. 

Talking  is  a  serial  response.  Many  of  our  sen- 
tences are  faithfully  reproduced  habits  that  have 
been  uttered  in  the  same  form  hundreds  of  times. 
These  stereotyped  sentences  are  often  imitation  of 
other  people 's  speech.  In  spite  of  stereotypisins,  we 
frequently  use  a  novel  combination  of  words.  This 
is  made  possible  by  the  fact  that  any  word,  when 
spoken,  is  a  stimulus  that  arouses  a  number  of  word 
reaction  tendencies,  because  nearly  any  word  has  in 
previous  speech  been  followed  now  by  one  word  and 
now  by  another.  Although  various  sequences  of 
words  are  available,  the  response  thresholds  at  the 
moment  determine  what  sequence  shall  occur. 

When  we  use  the  word  "abate,"  there  is  little 
doubt  but  that  this  will  be  followed  by  the  word 
" nuisance."  But  such  wTords  as  "eat,"  "carry," 
"push,"  or  "find"  have  been  followed  in  the  past 
by  so  great  a  variety  of  word  responses  that  it  is 
hard  to  predict  which  of  the  reaction  tendencies  pres- 
ent will  prevail. 

The  low  threshold  of  the  word  that  does  prevail 
is  determined  by  many  things.  First  of  all  there  is 
the  influence  of  words  uttered  shortly  before  by 
either  speaker  or  listener.    Many  of  the  words  we 


PERCEPTION  165 

use  when  talking  about  football  have  been  used  on 
previous  occasions  after  the  term  "football"  has 
been  introduced. 

An  intelligent  person  in  good  health  holds  to  the 
topic  of  conversation.  One  of  the  symptoms  in  in- 
sanity is  an  undirected  verbosity  in  which  the  tend- 
ency to  adhere  to  the  topic  of  conversation  is  lost, 
and  in  which  the  words  occur  without  regard  to  con- 
text. This  sort  of  speech  has  been  well  called  "word 
salad."  It  is  often  approximated  by  simple-minded 
and  excitable  people. 

In  addition  to  the  influence  of  verbal  context  there 
is  the  influence  of  non-verbal  situations  in  determin- 
ing our  choice  of  words.  The  facial  expression  of 
our  hearer,  the  fact  that  he  is  a  man  rather  than  a 
woman,  being  in  another's  house  rather  than  in  our 
own,  and  having  a  good  appetite  instead  of  having 
just  satisfied  it,  are  matters  that  determine  the 
words  we  say. 

Among  the  topics  most  tenaciously  adhered  to  in 
conversation  are  diet,  romance,  and  adventure.  The 
drive  toward  this  form  of  conversation  is  provided 
by  the  visceral  organization  of  man,  and  needs  but 
little  stimulation  from  external  conditions. 

Most  important  of  all  in  determining  the  form  of 
our  sentences  is  the  previous  non-verbal  perception 
of  the  objects  or  of  the  events  we  discuss.  Past 
events  dictate  the  words  we  use  in  their  description, 
as  these  words  are  in  part  delayed  responses  to  the 
described  events. 


166  GENERAL  PSYCHOLOGY 

The  internal  emotional  responses  play  an  impor- 
tant role  in  perception.  Just  as  things  may  "look" 
hard,  so  they  may  "look"  dangerous,  disgusting, 
beautiful,  or  annoying.  If  the  response  threshold  is 
high,  or  if  the  provocation  is  slight,  the  expression 
of  the  emotional  response  tendency  may  go  no  far- 
ther than  these  internal  changes.  As  a  result  of 
stronger  stimulation  and  reenforcement,  overt  emo- 
tional responses  may  result. 

At  Different  Times  a  Situation  May  Prompt  Us  to 
Different  Perceptions 

The  form  of  any  perception  is  determined  in  part 
by  the  combination  of  stimuli  that  affects  the  sense 
organs  at  the  time,  and  in  part  by  the  conditioned  re- 
sponses that  the  individual  has  previously  associated 
with  these  stimuli.  The  threshold  of  these  condi- 
tioned responses  varies  in  a  single  individual  ac- 
cording to  the  recency  with  which  the  responses  have 
been  performed,  and  according  to  the  nature  of  the 
behavior  in  which  he  has  just  been  engaged.  The 
alignment  of  pieces  on  a  chess  board  is  perceived 
most  thoroughly  by  a  player  who  is  in  practice.  A 
page  of  Virgil  may  be  almost  meaningless  to  a  per- 
son who  has  for  years  neglected  his  Latin.  Such  a 
recent  experience  as  reading  a  detective  story  may 
lower  our  threshold  of  perception  of  burglars.  Hav- 
ing run  out  of  gasoline  the  day  before  lowers  the 
threshold  of  perception  of  the  indicator  of  the  gas 


PERCEPTION  167 

tank.  After  an  accident  on  the  road  the  driver's 
perception  of  traffic  is  changed. 

Due  to  the  dependence  of  perception  on  habit,  the 
same  combination  of  stimuli  will  be  perceived  dif- 
ferently by  two  persons.  The  tea  taster's  percep- 
tion of  tea,  the  florist's  perception  of  roses,  the  fan- 
cier's perception  of  dogs,  and  the  entomologist's 
perception  of  bugs,  differ  from  the  corresponding 
perceptions  of  untrained  persons.  Each  of  us  has 
his  private  equipment  of  habit  and  perceives  any 
situation  accordingly. 

Because  response  thresholds  vary  from  time  to 
time,  a  combination  of  stimuli  may  be  perceived  now 
in  one  way  and  now  in  another.  The  words  "time 
flies"  may  be  perceived  as  a  statement  that  time  is 
fleeting  or  as  a  request  to  determine  the  rapidity 
with  which  flies  fly.  The  staircase  figure  (Figure 
26)  may  be  perceived  as  a  flight  of  steps  seen  either 
from  above  or  from  below.  Stimuli  that  may  lead  to 
either  of  two  radically  different  perceptions  are 
called  equivocal  stimuli.  Where  two  diverse  situa- 
tions have  several  elements  in  common,  these  sev- 
eral elements  occurring  alone  as  stimuli  may  lead  to 
a  perception  of  either  situation. 

Equivocal  stimuli  often  give  rise  to  false  percep- 
tions, which  may  be  rectified  by  further  acquaintance 
with  the  situation.  Such  a  false  perception  is  called 
an  illusion.  Reacting  to  a  piece  of  tin  foil  seen  on 
the  street  as  though  it  were  a  coin,  responding  to  a 
bit  of  floating  dust  in  the  air  as  though  it  were  a 


168 


GENERAL  PSYCHOLOGY 


house  moth,  running  away  from  the  sound  of  a  fall- 
ing object  in  the  woods  as  though  it  were  a  wild  ani- 
mal, appropriating  another  person's  umbrella  under 
the  impression  that  it  is  one's  own,  are  all  examples 
of  illusion. 


FlGUBE   26.      STAIRCASE   FIGURE.      THIS   MAT  BE   SEEN  AS   A   FLIGHT  OF 
STAIRS   VIEWED   FROM   ABOVE,   OR  AS   A   FLIGHT 
VIEWED   FROM    BELOW 


An  hallucination  is  a  response  tendency,  not  ini- 
tiated by  sensory  stimuli,  which  follows  a  sensory 
impulse  originating  in  some  part  of  the  nervous  sys- 
tem. It  is  often  the  result  of  degenerative  processes 
accompanying  nervous  disease,  but  frequently  oc- 
curs in  healthy  individuals.    All  hallucinations  con- 


PERCEPTION 


169 


form  to  reaction  tendencies  of  low  threshold.  The 
insane  patient  who  reports  that  he  hears  voices 
warning  him  of  the  treachery  of  an  acquaintance 
must  previously  have  acquired  reaction  tendencies 
of  suspicion  toward  the  person  in  question. 

Changes  in  the  sense  organs  themselves,  incident 
upon  circulation  and  upon  metabolism  in  general, 
provide  for  the  normal  individual  sufficient  sensory 
cues  for  hallucinations  of  a  simple  sort.  This  is 
most  likely  to  occur  when  he  is  in  a  half -waking  state 


Figure  27.    the  face  that  is  perceived  as  nearest  the  ohserver 
may  also  be  perceived  as  the  most  distant 


and  partially  isolated  from  sensory  stimuli.  It  is 
of  common  occurrence  for  a  person  to  report  that  his 
name  has  been  spoken  just  as  he  is  about  to  go  to 
sleep.  Visions  are  most  frequently  seen  in  the  dim 
light  of  bed  rooms. 

Our  perceptions  are  determined  not  only  by  the 
habits  we  have  acquired  but  also  by  the  kind  and  by 
the  intensity  of  the  sensory  stimulation  to  which  we 


170  GENERAL  PSYCHOLOGY 

happen  to  be  exposed.  Stimuli  may  occur  in  combi- 
nations of  practically  unlimited  diversity  and  no  two 
situations  are  ever  wholly  identical.  As  two  situa- 
tions, but  slightly  different,  may  cause  two  very  dif- 
ferent perceptions,  the  number  of  possible  percep- 
tions is  almost  unlimited. 

Compkomise  Responses  in  Perception 

Compromise  responses  have  already  been  de- 
scribed. As  we  walk  through  the  woods  the  direc- 
tion our  footsteps  take  is  a  compromise  of  the  many 
orientation  tendencies  that  are  aroused  by  rocks, 
trees,  and  the  contour  of  the  ground.  The  course  of 
a  bird  flying  through  the  forest  is  determined  by  the 
visual  stimuli  from  all  the  obstacles  it  must  avoid. 
There  seldom  occurs  an  isolated  response.  Most  re- 
sponses are  somewhat  distorted  by  the  total  behavior 
of  the  moment. 

Objects  and  events  are  never  perceived  independ- 
ently of  their  settings.  My  dollar  is  one  thing  and 
his  dollar  is  quite  another.  Food  at  meal  time  fur- 
nishes a  perception  very  different  from  that  of  food 
after  dinner.  Soap  experienced  together  with  towels 
and  water  and  soap  seen  on  a  druggist's  counter 
are  not  perceived  merely  as  soap.  A  word  has 
complete  meaning  only  in  its  context,  and  we 
perceive  short  sentences  as  wholes  and  not  as  lists 
of  words. 

Man  is  undoubtedly  of  all  animals  the  best  en- 


PERCEPTION  171 

dowed  with  neurological  mechanisms  for  compromise 
responses.  When  an  unfamiliar  combination  of 
stimuli  produces  a  resultant  reaction,  the  act  so  in- 
tegrated may  become  a  response  habit.  In  this  way 
perceptions  shift  their  content  and  grow  in  fitness 
and  complexity  as  a  result  of  the  successive  occur- 
rence of  slightly  different  assemblages  of  stimuli. 
Each  unusual  occurrence  in  a  situation  leaves  behind 
it  a  trace  of  compromise  that  becomes  a  part  of  later 
perceptions  of  events  somewhat  the  same. 

Perceptions  feom  Simultaneous  Stimuli 

There  is  no  one  sense  organ  in  the  skin  or  muscles 
by  which  we  perceive  things  as  hard,  soft,  rough, 
smooth,  wet,  dry,  greasy,  or  sticky.  In  comparison 
with  a  soft  object,  a  hard  object,  when  pressed  upon, 
gives  more  intense  stimulation  to  touch  and  pain 
organs  and  stimulates  a  smaller  area  of  the  skin. 
The  muscles  involved  when  we  lean  upon  such  an 
object,  or  when  we  grasp  it,  are  often  under  greater 
tension  than  if  the  object  were  soft. 

"When  we  draw  our  finger  along  a  surface  that  in- 
termittently stimulates  the  sense  organs  of  touch,  we 
say  that  it  is  rough.  "When  the  movement  stimulates 
the  same  organs  in  the  muscles,  but  when  the  stimu- 
lation of  the  sense  organs  of  touch  is  sustained  and 
not  intermittent,  we  call  the  surface  smooth. 

Perception  of  wetness  results  from  the  stimulation 
of  cold  organs  along  with  the  stimulation  involved 


172  GENERAL  PSYCHOLOGY 

in  the  perception  of  smoothness.  The  perception  of 
greasiness  requires  the  absence  of  the  fine  vibration 
of  the  skin  that  is  characteristic  of  drawing  the  hand 
over  a  surface  free  from  grease.  A  silver  spoon 
always  feels  more  greasy  than  a  varnished  table  top 
because  the  polished  metal  surface  offers  less  fric- 
tion. Objects  seem  sticky  when,  on  releasing  them, 
the  skin  adheres  somewhat  to  the  objects  and  is  dis- 
placed outwardly.  The  perception  of  tickling  nec- 
essitates the  contraction  of  muscles,  especially  those 
adjacent  to  the  area  stimulated,  and  always  contains 
an  emotional  component. 

The  identification  of  objects  by  skin  contact  and 
manipulation  alone,  is  called  stereognosis.  If  we 
reach  behind  a  screen  and  feel  an  object,  we  can  usu- 
ally tell  what  it  is.  A  watch  is  colder  and  heavier 
than  a  pencil.  The  surfaces  of  the  two  objects  when 
rubbed  afford  different  stimulation  to  sense  organs 
in  the  skin  and  muscles.  As  the  finger  follows  the 
contours,  the  position  and  movement  of  muscles  and 
joints  afford  a  characteristic  stimulation.  A  lack 
of  resistance  in  the  loose  parts  of  the  watch  and  the 
joliability  of  the  rubber  end  of  the  pencil  furnish  sen- 
sory cues  to  the  respective  perceptions. 

Space  Perception 

The  perception  of  distance  or  depth,  and  space 
perception  in  general,  consist  either  of  such  respon- 
ses as  saying,  "That  house  is  about  a  mile  away," 


PERCEPTION  173 

or  "This  table  is  four  feet  long,"  or  of  such  respon- 
ses as  throwing  a  stone  at  a  mark,  jumping  from 
one  spot  to  another,  setting  out  to  walk  to  a  certain 
objective,  reaching  for  an  object  near  at  hand,  sit- 
ting down  on  a  chair  that  seems  appropriately 
placed,  or  they  may  consist  of  such  responses  as  in- 
hibiting any  overt  reaction,  or  giving  attention  to 
objects  or  turning  away  from  them  according  as 
their  position  causes  one  sort  of  stimulation  or 
another. 

Visual  Space  Pekception 

As  a  stimulating  object  changes  its  distance  from 
the  eye  there  is  a  change  in  the  nature  of  its  stimu- 
lation and  a  change  in  the  character  of  the  responses 
that  are  instinctively  given.  Visual  perception  of 
distance  or  depth  depends  ultimately  upon  these  two 
facts.  We  shall  consider  first  the  instinctive  respon- 
ses of  fixation,  binocular  accommodation,  and  mon- 
ocular accommodation. 

When  a  spot  of  light  falls  upon  any  part  of  the 
retina  other  than  the  fovea,  there  is  an  instinctive 
tendency  so  to  move  the  eyeball,  and  possibly  the 
head  as  well,  that  the  light  shall  be  brought  to  bear 
upon  the  fovea.  This  response  is  called  fixation. 
It  is  effected  by  the  contraction  of  muscles  external 
to  the  eyeball.  These  muscles  include  the  four  recti 
muscles  and  the  two  oblique  muscles  of  each  eye. 
(Figure  2.)    When  the  same  object  stimulates  both 


174  GENERAL  PSYCHOLOGY 

eyes,  each  eye  tends  to  fixate.  This  double  fixation  is 
called  binocular  accommodation. 

A  straight  line  extending  outward  from  the  center 
of  the  fovea  and  passing  through  the  center  of  the 
lens  is  called  the  axis  of  vision.  When  binocular 
accommodation  occurs  for  a  distant  object,  the  axes 
of  vision  of  the  two  eyes  are  practically  parallel. 
When  we  look  at  a  near  object,  these  lines  of  vision 
form  a  greater  angle.  The  degree  of  convergence 
increases  with  the  nearness  of  the  stimulating  object 
and  produces  muscle  strain.  This  muscle  strain  af- 
fords movement-produced  stimuli  of  varying  degrees 
of  intensity.  The  intensity  and  the  distribution  of 
this  stimulation  in  the  external  eye  muscles  is  one 
of  the  sensory  cues  to  the  perception  of  distance. 

In  order  that  the  image  of  a  near  object  may  be 
clearly  focused  on  the  retina,  the  ciliary  muscle  and 
the  iris  muscle  must  be  contracted  (see  the  descrip- 
tion of  the  eye  in  Chapter  1).  The  contraction  nec- 
essary to  accomplish  this  clearness  of  focus  is  called 
monocular  accommodation.  The  eye  at  rest  is  ac- 
commodated for  far  vision.  The  nearer  the  object, 
the  greater  is  the  contraction  in  the  circular  fibres 
of  the  ciliary  and  the  iris  muscles,  and  the  greater  is 
the  stimulation  to  the  sense  organs  that  are  in  these 
muscles  and  in  their  attachments.  This  varying 
stimulation  serves  as  another  sensory  cue  to  the 
visual  perception  of  distance.  The  stimulus  that 
effects  these  instinctive  movements  of  monocular 
accommodation  is  a  blurred  image.    It  is  probable 


PERCEPTION  175 

that  the  stimuli  derived  from  movements  of  binocu- 
lar accommodation  also  produce  instinctive  monocu- 
lar adjustment. 

Along  with  the  varying  degree  of  remoteness  of 
an  object  there  go  changes  of  stimulation  other  than 
those  that  cause  instinctive  binocular  and  monocular 
accommodation.  The  nearer  an  object,  the  larger  is 
its  retinal  image.  This  is  a  sensory  cue  for  per- 
ceiving the  distance  of  all  objects  of  familiar  pat- 
tern. As  all  the  one-cent  pieces  we  have  ever  seen 
have  been  uniformly  about  three-quarters  of  an  inch 
in  diameter,  we  have  developed,  through  learning, 
different  responses  of  approaching  and  reaching  for 
pennies,  according  to  the  size  of  the  image  they  cast 
on  the  retina.  As  a  tuft  of  cotton  has  no  uniform 
size,  the  size  of  the  retinal  image  it  casts  is  not  very 
suggestive  of  its  distance. 

Near  objects  show  a  clearness  of  detail  and  a 
differentiation  of  shadows  not  seen  in  objects  that 
are  far  away.  This  difference  in  stimulating  effect 
we  learn  to  interpret  perceptually  by  appropriate 
responses.  The  indistinctness  of  things  far  away 
is  due  mainly  to  particles  in  the  intervening  atmos- 
phere. In  the  clear  air  of  Colorado  distant  moun- 
tains look  deceptively  near.  Trees  seen  through  a 
fog  look  larger  than  they  really  are  because,  being 
indistinct,  they  are  wrongly  perceived  as  farther 
away.  Being  perceived  as  farther  away,  they  are 
consequently  responded  to  as  though  they  were 
larger  trees,  for  larger  trees  farther  away  would 


176  GENERAL  PSYCHOLOGY 

cast  visual  images  of  the  size  the  eye  receives.  This 
effect  is  utilized  in  the  illusion  of  distance  that  is 
secured  on  the  stage  by  interposing  a  fish  net  be- 
tween the  back  drop  and  the  audience. 

Far  away  objects  have  a  blue  appearance  due  to 
the  polarization  of  sunlight  by  atmospheric  parti- 
cles, and  this  provides  another  sensory  cue  for  per- 
ception of  depth. 

Farther  objects  may  be  partially  obscured  by 
nearer  objects,  and  when  so  seen  are  perceived  as 
more  remote.    (See  Figure  28.)    Due  to  the  fact  that 


Figure  28.    the  peak  is  perceived  as  behind  the  apple  because  it 
is  partially  hidden  by  the  apple 


most  things  extend  upward  from  the  ground,  distant 
objects  are  ordinarily  seen  over  the  tops  of  objects 
near  at  hand.  Thus  the  objects  higher  in  the  field 
of  vision  are  likely  to  seem  the  more  remote.  (See 
Figure  29.) 

If  a  far  object  is  fixated  and  the  head  is  moved 
from  side  to  side,  intervening  objects  in  the  field  of 
vision  appear  to  move  in  a  direction  opposite  to  that 
of  the  head  movement.    If  a  near  object  is  fixated, 


PERCEPTION 


177 


movement  of  the  head  is  accompanied  by  the  appar- 
ent movement  of  more  distant  objects  in  the  same 
direction.  When  the  eye  is  at  rest,  the  retinal  im- 
age of  an  object  passing  in  the  foreground  shifts 
more  rapidly  than  that  of  the  object  moving  at  the 
same  speed  in  the  distance. 

"When  walking  or  when  riding  in  a  train,  the  fixa- 
tion of  near  objects  in  the  landscape  must  be  ac- 
complished by  more  rapid  eye  movements  than  the 
fixation  of  distant  objects.    All  these  differences  of 


FlGUEE  29.     OBJECTS  HIGHEE  IN  THE  FIELD  OF  VISION  TEND  TO  BE  PER- 
CEIVED AS   MORE   DISTANT 


stimulation  serve  as  sensory  cues  to  the  perception 
of  depth. 

An  object  seen  both  with  the  right  eye  and  with  the 
left  eye  is  seen  from  the  two  different  positions,  so 
that  each  eye  views  a  different  part  of  the  object's 
surface.  Unless  it  is  bi-laterally  symmetrical  and 
of  a  certain  regular  surface  without  shadows,  the 
images  it  casts  upon  the  two  retinae  will  be  dissimi- 
lar. The  nearer  an  object  is  to  the  eye,  and  the 
greater  the  consequent  binocular  convergence,  the 
more  dissimilar  are  the  two  retinal  images.  Not 
only  are  the  two  images  that  are  cast  by  the  same 


L78  GENERAL  PSYCHOLOGY 

object  different,  but  these  images  are  commonly 
seen  by  each  eye  against  a  different  background. 
Til-.  I  _ .  .  •:•  of  dissimilarity  of  these  images,  to- 
gether with  the  unlikeness  of  their  backgrounds,  is 
:her  sensory  cue  to  the  perception  of  depth. 
Visual  space  perception  includes  responses  to  ob- 
jects seen  above,  below,  to  the  right,  or  to  the  left. 
The  difference  in  stimulation  that  serves  to  distin- 
guish such  perceptions  from  each  other  is  twofold. 
The  part  of  the  retina  stimulated  is  different,  and, 
if  fixation  follows,  the  eye  movements  involved  in 
fixating  the  stimulating  object  are  different.  These 
eye  movements  afford  various  movement-produced 
stimuli. 

Visual  Perception  of  Object- 

ts  give  not  only  such  stimuli  as  elicit  space 
perc- 1  v.  :..  but  furnish  their  own  characteristic  pat- 
tern and  color  stimulation.    This  printed  page  con- 
tain- Is       many  different  patterns  and  the  cor- 
onding  image-patterns  on  the  retina  serve  as 
cues  for  many  different  perceptions.   As 
the  page  is  moved  away  from  the  eye.  the  imag  - 
me  smaller,  but  we  call  the  patterns  the  same. 
It  is  probable  that  the  similarity  of  our  responses 
to  an  object  seen  at  different  distances  is  due  to  the 
fact  that  an  object  affords  a  continuous  stimulation 
as  it  moves  toward  us  or  away  from  us.    The  pattern 
of  the  letter  H  is  seen  in  all  sizes  as  the  letter  ap- 


PERCEPTION  179 

proaches  the  eye.  His  mother  seen  at  a  distance  of 
three  feet  looks  to  the  baby  like  his  mother  seen  at  a 
distance  of  ten  feet  because  he  has  continuously 
fixated  her  and  has  maintained  other  responses 
toward  her  as  she  changes  her  position.  If  it  were 
not  for  this  gradual  change  of  size  of  images  cast  by 
approaching  and  receding  objects,  it  is  probable  that 
all  visual  patterns  of  dissimilar  size  would  arouse 
wholly  different  perceptions.  Due,  however,  to  this 
sequence  of  stimulation,  and  to  the  overlapping  of 
responses,  patterns  of  different  size  often  arouse 
practically  the  same  perception. 

Because  of  another  sequence  of  stimulation,  pat- 
terns of  dissimilar  form  tend  to  arouse  similar  per- 
ceptions. As  our  friend  turns  his  head,  he  casts 
upon  our  retina  an  image  of  gradually  changing 
shape.  All  this  time  we  are  acting  toward  him  in  the 
same  way.  For  this  reason  the  full  face  and  the 
profile  photographs  of  our  friend  seem  much  more 
alike  to  us  than  the  full  face  and  the  profile  photo- 
graphs of  a  stranger.  As  we  handle  a  cylindrical 
tobacco  can,  the  image  of  its  top  changes  from  a  cir- 
cular image  to  an  elliptical  image  whose  smaller 
axis  gradually  diminishes.  The  degree  of  resem- 
blance of  two  patterns  certainly  depends  in  part  on 
their  relative  position  in  such  a  temporal  sequence 
of  stimulation. 

Retinal  stimulation  from  objects  differs  in  color, 
and  various  combinations  of  color  may  enter  into 
the  retinal  pattern.    Certain  colors  are  characterise 


180  GENERAL  PSYCHOLOGY 

tic  of  particular  objects  and  substances,  and  the  state 
of  objects  is  often  indicated  by  variations  in  color. 
We  avoid  picking  up  the  poker  by  the  red  end;  we 
cease  cooking  food  when  it  is  sufficiently  brown ;  and 
we  eat  a  red  apple  rather  than  a  green  one. 

Auditory  Space  Perception 

The  direction  of  an  object  is  roughly  perceived  by 
means  of  the  ears,  because  when  the  object  is  not  in 
the  median  plane,  it  stimulates  one  ear  more  than 
the  other.  The  direction  of  a  sounding  object  that 
is  in  this  median  plane,  in  front,  above,  or  behind  us, 
is  perceived  very  inaccurately.  The  evidence  of  a 
person  who  testifies  in  court  that  he  heard  a  revolver 
shot  just  ahead  of  him  on  a  dark  night  should  never 
be  admitted,  although  his  testimony  that  the  shot 
came  from  the  right  may  be  of  considerable  value. 

The  direction  of  a  continuous  sound  may  be  fairly 
well  located  by  turning  the  head  toward  the  side  at 
first  more  strongly  stimulated.  When  the  sound  is 
heard  equally  by  the  two  ears,  the  face  is  directed 
toward  the  source  of  the  sound.  The  shape  of  the 
external  ear  is  responsible  for  slight  differences  in 
the  intensity  of  a  sound  as  it  comes  from  one  direc- 
tion or  another.  For  this  reason  we  may  have  a 
meager  perception  of  an  object's  being  before  or  be- 
hind, even  when  we  do  not  move  the  head. 

If  a  familiar  object  emits  a  sound  of  fairly  con- 
stant intensity,  this  intensity  is  a  cue  for  perceiving 


PERCEPTION  181 

how  far  away  the  object  is.  Telephone  bells,  fog 
horns,  bumble  bees,  alarm  clocks,  automobiles,  and 
even  footsteps,  human  voices,  rustling  leaves,  and 
falling  objects  arouse  distance  perceptions  accord- 
ing to  the  intensity  of  the  stimulation.  The  inten- 
sity of  a  wholly  unfamiliar  sound  would  be  no  cue  to 
the  remoteness  of  its  source. 

The  echoes  that  are  reflected  from  objects  furnish 
a  sensory  aid  to  our  perception  of  distance.  These 
echoes  are  notably  of  assistance  to  the  blind,  who 
find  it  easier  to  avoid  obstacles  when  they  walk  with 
heavy  shoes  on  resounding  pavements  or  when  they 
tap  the  ground  with  a  stick.  If  the  reflecting  surface 
is  several  feet  away,  not  only  the  intensity  and  the 
direction  of  the  echo,  but  the  time  interval  between 
the  original  noise  and  its  echo  may  assist  in  the  dis- 
tance perception. 

Auditoey  Perception  of  Objects 

The  sounds  we  hear  about  us  are  combinations  of 
simple  tones,  each  tone  having  a  different  pitch.  A 
tone  is  made  up  of  simple  vibrations  of  a  single 
rate.  Its  pitch  depends  upon  the  rate  or  frequency 
of  these  vibrations.  Rapid  vibrations  are  high 
pitched  and  slow  vibrations  are  low  pitched.  Any 
complex  sound  may  be  analyzed  into  its  pure  tone 
components.  When  a  harp  string  is  plucked,  the 
resulting  note  has  a  fundamental  tone,  caused  by  the 
string's  vibrating  as  a  whole,  and  a  great  many  tones 


182  GENERAL  PSYCHOLOGY 

of  higher  pitch  (overtones)  that  are  caused  by  the 
more  rapid  vibrations  of  parts  of  the  string.  A 
well  made  tuning  fork  has  practically  no  overtones 
so  that  the  sound  it  produces  approximates  a  pure 
tone. 

Any  note,  such  as  middle  C,  is  different  when 
sounded  on  a  piano,  a.  violin,  a  banjo,  or  a  harp. 
This  difference  is  called  a  difference  of  timbre,  and 
is  due  to  differences  in  the  intensities  of  the  various 
overtones  that  each  instrument  produces.  Voices 
of  men,  women,  and  children  differ  in  timbre  and 
this  is  also  true  of  the  voices  of  individuals. 

The  overtones  in  a  musical  sound  have  vibration 
rates  that  are  all  multiples  of  the  vibration  rate  of 
the  fundamental  tone.  A  noise  is  made  up  of  a 
combination  of  tones  whose  vibration  rates  are  in 
no  simple  ratio.  The  sounds  of  a  passing  locomotive, 
of  paper  being  crumpled,  and  of  a  slamming  door, 
are  complexes  of  tones  in  disorderly  confusion  and 
are  called  noises. 

The  diversity  of  noises  is  due  to  the  peculiar 
structure  of  the  objects  whose  vibration  causes  them, 
and  so  each  kind  of  object  has  its  characteristic 
sound.  These  characteristic  sounds  serve  as  the 
cues  for  auditory  perception  of  objects.  The  sounds 
of  sawing,  hammering,  or  extracting  rusty  nails  can 
hardly  be  mistaken.  We  distinguish  the  passing 
automobile  from  the  passing  street  car.  The  jingling 
of  coins  and  the  jingling  of  a  bunch  of  keys  are  suffi- 
ciently different  to  afford  different  perceptions. 


PERCEPTION  183 

Sounds  may  shift  from  one  fundamental  pitch, 
from  one  intensity,  or  from  one  timbre  to  another. 
This  shifting,  as  well  as  a  certain  duration  and 
rhythm,  is  characteristic  of  certain  objects  and 
events.  Words,  and  vocalization  in  general,  more 
than  any  other  sounds,  depend  upon  this  change  of 
tonal  composition  and  this  modulation  of  intensity 
for  their  effectiveness  as  sensory  cues. 

Olfactoky  Perception 

Odor  stimuli  are  of  little  use  as  sensory  cues  for 
perception  of  the  direction  of  the  odorous  object. 
This  is  because  a  change  of  orientation  changes  but 
little  the  intensity  of  odor  stimulation.  The  gases 
that  emanate  from  an  object  and  that  are  borne  on 
the  wind  may  affect  our  sense  organs  long  after 
the  source  of  the  odor  has  been  removed.  Objects 
may  be  seen  and  heard  only  when  present,  and 
changes  of  position  modify  their  stimulation.  Be- 
cause of  this,  light  and  sound  are  the  best  cues  for 
direction  perception. 

Energetic  emotional  responses,  many  of  them  in- 
stinctive, are  given  to  odor  stimuli.  This  drive  re- 
sults in  trial  and  error  behavior  until  a  more  defi- 
nite spatial  perception  of  the  object  is  obtained 
through  other  senses.  There  is  a  compensation  for 
the  absence  of  odor  space  perception  in  this  drive- 
aroused  trial  and  error  behavior.  The  odor  of  food 
starts  the  animal  on  its  search,  although  it  may  have 


184  GENERAL  PSYCHOLOGY 

no  perception  of  where  the  food  is.  As  it  nears  the 
food,  the  odor  becomes  more  intense  and  the  animal's 
explorations  more  thorough  at  this  spot. 

A  hound,  crossing  the  trail  of  a  fox,  probably  does 
not  perceive  by  the  use  of  his  nose  alone  the  direc- 
tion in  which  the  fox  has  gone.  If  he  proceeds  in 
the  wrong  direction,  the  trail  becomes  fainter, 
whereupon  he  is  apt  to  turn  about  and  follow  a  scent 
that  becomes  increasingly  warmer.  As  he  ap- 
proaches the  fox,  his  excitement  increases  and  this 
keeps  him  from  turning  back  once  he  is  rightly 
headed.  The  ability  of  an  ant  to  take  the  right  di- 
rection when  placed  on  a  trail  is  probably  due  to  its 
familiarity  with  the  surface  over  which  it  has  fre- 
quently walked,  and  not  due  to  any  mysterious  odor 
mechanism  for  keeping  its  homeward  course. 

Different  odors  arouse  different  emotions  and 
lower  the  thresholds  of  particular  reactions.  This 
is  often  the  result  of  conditioning,  but  is  sometimes 
instinctive.  Kittens,  before  their  eyes  are  opened, 
and  without  previous  experience  of  puppies,  will 
raise  the  head  and  "spit"  when  a  puppy  is  intro- 
duced into  their  cage.  The  odor  of  a  possible  mate 
causes  general  restlessness  among  most  lower  ani- 
mals and  lowers  the  threshold  of  mating  responses. 
The  odor  of  food  causes  hunger  and  the  odor  of 
spoiled  food  causes  nausea.  The  ant  stimulated  by 
a  strange  hive  odor  shows  fear,  and,  when  con- 
fronted with  one  of  its  own  group  that  has  been 
artificially  perfumed  with  the  odor  of  a  strange  hive, 


PERCEPTION  185 

shows  fight.  The  odor  of  a  crowd  probably  has  a 
quieting  and  depressing  effect  upon  human  beings. 

The  olfactory  lobes  in  the  human  brain,  as  com- 
pared with  those  in  the  brains  of  most  lower  ani- 
mals, are  relatively  small,  and  man's  odor  percep- 
tions are  relatively  meager.  Standing  upon  his  hind 
legs,  man  has  a  wider  visual  horizon  and  less  oppor- 
tunity for  bringing  his  nose  in  contact  with  objects. 
Thus  his  increasing  dependence  upon  vision  seems  to 
have  been  accompanied  by  a  lessened  dependence  on 
odor  perceptions. 

The  poverty  of  man's  odor  perceptions  is,  how- 
ever, not  wholly  due  to  the  lack  of  an  adequate  mech- 
anism. With  careful  practice  a  great  improve- 
ment in  odor  perceptions  is  possible.  Blind  persons, 
tea  and  wine  tasters,  and  connoisseurs  in  food  often 
show  an  interesting  superiority  in  odor  discrimina- 
tion. 

The  diversity  of  odor  stimuli,  their  capacity  for 
arousing  dissimilar  responses,  and  the  many  possi- 
ble combinations  of  these  stimuli  enable  us  to  dis- 
tinguish objects  with  considerable  accuracy  by 
means  of  this  sense.  Not  only  individual  objects 
but  classes  of  objects  as  well  have  their  characteris- 
tic odor.  Things  that  are  not  seen  may  often  be 
recognized  by  their  scent  as  tobacco,  cheese,  frying 
bacon,  coffee,  or  fresh  bread.  All  marine  animals 
smell  somewhat  alike.  So  do  most  flowers  and  most 
fruits. 

The  compromise  reactions,  which  grow  up  about 


186  GENERAL  PSYCHOLOGY 

objects  as  a  result  of  our  responding  to  the  various 
stimuli  that  they  offer,  become  attached  to  the  odor 
stimuli  that  the  objects  furnish,  and  in  this  way  in- 
stinctive responses  of  one  sort  are  often  replaced 
by  learned  responses  of  quite  another.  The  odors 
of  whiskey,  tobacco,  cheese,  and  clams  are  distaste- 
ful to  most  children,  but  are  popular  among  adults. 

KlNAESTHETIC  AND  STATIC  PERCEPTION 

The  perception  of  objects  from  muscle-sense  cues 
has  already  been  considered.  Nearly  all  bodily  re- 
sponses are  determined  in  part  by  muscle  and  static 
sense  stimulation  that  results  from  our  position  and 
our  movement.  Without  movement-produced  stim- 
uli to  the  proprioceptors  in  the  legs  we  would  be 
unable  to  walk.  Jar  and  displacement  of  muscles 
and  viscera  give  us  perceptions  of  being  jolted, 
dropped,  or  carried  about. 

Our  perception  of  rotary  direction  is  not  confined 
to  instinctive  responses  of  head  turning  and  eye 
movements.  Stimulation  of  the  semicircular  canals 
brings  about  many  learned  responses  that  maintain 
equilibrium  in  such  acts  as  dancing,  boxing,  or  tennis 
playing. 

Touch  Perception 

The  way  we  identify  the  part  of  the  body  that  is 
touched  needs  no  elaborate  explanation.    A  percep- 


PERCEPTION  187 

tion  is  always  a  response  and  the  stimulation  of  dif- 
ferently located  sense  organs  naturally  provokes 
different  responses.  To  a  touch  on  the  palm  of  his 
left  hand  a  baby  responds  by  closing  that  hand. 
Pricked  on  the  right  toe,  he  flexes  the  right  leg. 
Superimposed  upon  these  instinctive  movements  are 
the  learned  responses  given  to  objects  that  he  sees 
in  contact  with  his  body,  and  that  he  feels  in  the  pro- 
cess of  manipulation. 

Time  Perception 

The  sequence  and  duration  of  events  in  the  exter- 
nal world  are  as  real  as  the  objects  that  the  world 
contains.  The  common  sense  justification  for  this 
view  is  the  fact  that  events  keep  time  with  each 
other.  Two  objects  that  are  dropped  together  from 
the  same  height  strike  the  ground  together.  Every 
time  they  drop  the  same  number  of  seconds  is  ticked 
off  on  the  watch.  Bodily  functions  are  also  syn- 
chronized with  external  events  and  with  each  other. 
Our  intestinal  tract  is  a  not  inaccurate  time  piece, 
and  we  know  the  lunch  hour  by  our  peristalsis  as  well 
as  by  the  clock.  Thus  we  have  an  orderliness  of 
stimulation  that  determines  an  orderliness  of  per- 
ceptual responses. 

The  perception  of  duration  involves  some  such 
response  as  saying  to  ourselves,  "While  we  have 
been  talking,  the  bank  has  probably  closed  for  the 
day,  the  postman  has  come  and  gone,  and  the  train 


188  GENERAL  PSYCHOLOGY 

on  which  our  friends  left  has  reached  the  city."  We 
are  assisted  in  this  perception  by  knowing  that  the 
bank  closes,  the  postman  comes,  and  the  train  reaches 
its  destination  all  at  the  same  time.  We  would  be 
much  more  certain  that  all  these  events  have  oc- 
curred if  we  were  to  look  at  our  watch,  but  even  in 
the  absence  of  a  watch  we  are  likely  to  be  correct  in 
our  perception. 

Men  have  learned  that  of  all  the  orderly  changes 
in  the  external  world,  the  series  of  changes  in  the 
position  of  the  stars  with  reference  to  fixed  points 
in  an  observatory  is  the  most  dependable.  This 
simply  means  that  from  knowing  the  hour  angle  of 
a  star  we  can  infer  more  concerning  other  events 
than  from  knowing  the  stage  of  completion  of  any 
other  orderly  sequence  found  in  nature.  Because 
of  this  we  call  astronomical  events  the  most  regu- 
larly recurrent  and  accept  them  as  a  convenient 
standard  of  reference. 

Our  perception  of  time,  though  nearly  always 
aided  by  periodic  stimuli  from  orderly  events  in  our 
environment,  may  be  independent  of  these  stimuli. 
It  is  by  no  means  impossible  to  guess  successfully 
the  amount  of  time  that  has  elapsed  since  we  entered 
the  room.  The  question  how  we  do  this  may  be 
partly  answered  by  recalling  the  facts  of  forgetting. 

When  an  act  has  been  performed  once  and  is  then 
performed  again,  the  ease  of  the  second  performance 
depends  upon  the  amount  of  time  that  has  elapsed 
since  the  first.    This  ease  of  performance,  or  degree 


PERCEPTION  189 

of  positive  adaptation,  attaches  to  reminiscences  as 
well  as  to  overt  acts.  When  we  ask  ourselves  how 
long  we  have  been  sitting  here,  we  rehearse  the  events 
that  occurred  when  we  entered  the  room.  This 
rehearsal  involves  looking  at  the  door  through  which 
we  entered,  making  minimal  movements  that  corre- 
spond to  such  acts  as  entering,  saying  what  was  said 
at  that  time,  or  taking  our  seats.  The  amount  of 
positive  adaptation  that  exists  in  these  acts  of  re- 
hearsal after  any  lapse  of  time  is  a  cue  for  our  per- 
ception of  the  length  of  time  that  has  passed.  Cues 
of  this  sort  are  acknowledged  in  popular  speech  by 
such  words  as  "I  remember  it  as  though  it  were  yes- 
terday" or  "The  boat  has  just  whistled.' ' 

A  yet  more  effective  cue  to  our  perception  of  dura- 
tion is  our  recalling  the  acts  or  events  that  have  filled 
the  time  in  question.  Recalling  events  is  not  possi- 
ble unless  there  were  perceptual  responses  when  the 
events  took  place,  and  recall  is  a  somewhat  incom- 
plete repetition  of  these  responses. 

All  events  that  fill  any  period  of  time  vary  more 
or  less  in  rate  of  occurrence  when  referred  to  the 
astronomical  standard,  but  many  of  them  are  suffi- 
ciently periodic  to  be  dependable  as  measures  of 
time.  Pulse,  respiration,  and  the  rhythm  of  walk- 
ing, talking,  or  eating  are  sufficiently  periodic  to  en- 
able us  to  perceive  time  as  long  or  short  according 
as  it  contains  more  or  fewer  of  these  events.  The 
recollection  of  many  diverse  events  may  also  enter 
into  our  perception  of  time. 


190  GENERAL  PSYCHOLOGY 

The  increasing  fatigue  that  results  from  main- 
taining a  bodily  posture  is  significant  of  the  time 
that  has  elapsed  since  the  posture  was  taken  up.  So 
also  is  the  increasing  stimulation  from  holding  the 
breath  during  short  intervals  of  close  attention.  An 
interval  seems  longer  when  the  muscles  are  tense  and 
the  respiration  and  pulse  are  rapid. 

Judgment 

Even  the  simplest  reflex  is  not  given  immediately 
following  stimulation.  There  is  a  period  of  latency 
in  both  sense  organ  and  muscle,  and  some  time  is  re- 
quired for  the  nervous  impulse  to  traverse  the  re- 
flex arc.  Probably  the  shortest  reflex  time  is  .02 
second. 

If  we  are  asked  to  respond  to  the  sound  of  a  bell 
by  lifting  the  hand  as  quickly  as  possible,  the  inter- 
val between  stimulus  and  response  is  found  to  be 
about  .15  second.  This  is  perception  in  its  simplest 
form. 

The  perception  of  the  more  complex  situation  that 
involves  speaking  the  name  of  a  familiar  object  ex- 
posed to  view  requires  about  .5  second.  More  elabo- 
rate perceptual  responses  to  complex  situations  re- 
quire a  still  longer  time. 

Perceptions  of  situations  that  contain  a  novel  com- 
bination of  stimuli  have  a  comparatively  long  reac- 
tion time,  and  these  perceptions  we  call  judgments. 
There  is  no  sharp  distinction  between  slow  percep- 


PERCEPTION  191 

tions  and  rapid  judgments.  The  slowness  that  char- 
acterizes judgment  may  be  due  to  any  one  of  several 
causes. 

The  simplest  cause  for  delay  is  the  weakness  or 
meagerness  of  the  sensory  stimulation.  Music  heard 
faintly  in  the  distance  may  not  at  once  be  recognized 
as  any  particular  melody.  Objects  seen  in  the  twi- 
light are  identified  with  difficulty.  An  unfinished 
drawing  may  require  a  moment  of  study  before  we 
decide  what  it  represents. 

In  the  presence  of  equivocal  stimuli  the  final  per- 
ception is  often  delayed  until  facilitating  habits  are 
brought  into  play.  We  may  waken  from  sleep  to 
find  the  odor  of  smoke  in  the  house.  No  elaborate 
perception  may  result  until  it  dawns  on  us  that  we 
read  in  last  night's  paper  of  a  forest  fire  in  the 
neighborhood.  In  this  way  a  perception  may  be  com- 
pleted as  a  result  of  the  slow  action  of  reinforce- 
ments that  we  already  possess,  and  without  further 
explanation  of  the  objective  situation. 

A  novel  combination  of  stimuli  brings  about  a 
compromise  response,  and  this  response  is  slower 
than  one  that  has  been  practised.  When  we  meet  a 
friend  who  has  removed  his  mustache,  our  percep- 
tion is  both  slow  and  changed  in  character.  If  the 
objects  surrounding  the  bee  hive  have  been  moved 
about,  the  returning  bee  shows  excitement  and  takes 
a  longer  time  to  enter  the  hive.  In  driving  an  un- 
familiar automobile  our  responses  are  less  prompt 
and   necessarily    modified.      These    responses    are 


192  GENERAL  PSYCHOLOGY 

changed  in  character  because  a  different  combination 
of  neural  mechanisms  has  been  called  into  play  by  a 
new  aggregation  of  stimuli.  The  lengthened  time 
of  responses  is  a  result  of  the  interference  between 
the  mechanisms  involved.  Probably  no  two  respon- 
ses are  wholly  compatible,  and  in  extreme  cases  the 
interference  may  result  in  mutual  inhibition. 

A  dog  that  is  first  trained  to  come  when  his  master 
calls  him  may  later  respond  to  the  call  of  a  stranger, 
even  though  the  stranger's  appearance,  tone  of 
voice,  and  odor  may  differ  from  those  of  his  master. 
The  dog's  response  depends  upon  both  the  similarity 
and  the  differences  between  the  new  and  the  old.  A 
baby  that  has  learned  to  say  "duck"  while  looking 
at  the  duck  in  his  picture  book  is  likely  to  disregard 
differences  and  to  call  any  bird  a  duck.  If  a  hat  is 
sailed  over  the  chicken  yard,  the  chicks  may  run  to 
cover,  giving  the  response  that  is  customary  when  a 
hawk  appears.  A  hunting  dog  may  be  thrown  into 
great  excitement  if  his  master  leaves  the  house 
carrying  a  broomstick  as  though  it  were  a  gun.  In 
all  these  cases  the  animals  have  responded  to  those 
stimuli  in  the  new  situations  that  are  identical  with 
stimuli  occurring  in  the  original  situations.  The  new 
features  may  sometimes  greatly  modify  the  response 
and  may  sometimes  be  almost  wholly  disregarded. 
In  man,  and  to  some  extent  in  lower  animals,  these 
'new  features  commonly  bring  into  play  reaction 
tendencies  that  either  inhibit  or  facilitate  an  habitual 
response,  or  that  result  in  a  compromise  response. 


PERCEPTION  193 

Counterfeit  money  is  sufficiently  different  from 
real  money  to  furnish  a  cue  for  its  rejection. 
A  stranger  may  look  almost  like  an  acquaintance, 
but  a  minor  dissimilarity  keeps  us  from  speaking  to 
him.  We  may  be  about  to  claim  a  trunk  in  the  bag- 
gage room  until  we  observe  some  strange  character- 
istic about  it  that  causes  us  to  search  further.  In 
these  ways  response  tendencies  are  prevented  by 
our  taking  note  of  some  detail  in  the  new  situation 
that  was  absent  when  the  response  was  learned. 

One  of  the  laboratory  guinea-pigs  had  in  its  cage 
a  paste-board  nest-box  with  an  entrance  on  the  side. 
One  day  it  gnawed  a  small  hole  in  the  top  of  the  nest- 
box  and  immediately  afterwards,  on  being  given  a 
piece  of  carrot,  sat  down  beside  this  hole  to  eat.  The 
food  accidentally  fell  through  the  hole  into  the  nest- 
box  and  the  animal  made  a  vain  effort  to  crawl 
through  the  small  hole  to  recover  the  food.  Through 
the  hole  it  could  see  and  smell  both  the  food  and  the 
bedding  in  the  interior  of  the  box.  Without  repeat- 
ing the  effort  to  get  through  the  hole,  it  scrambled 
down  the  side,  ran  through  the  entrance,  and  seized 
the  food.  This  response,  though  facilitated  by  the 
food,  was  of  course  given  to  the  familiar  bedding, 
but,  because  the  food  and  bedding  were  adjacent,  the 
movement  led  to  the  food.  If  the  bedding  had  not 
been  present,  the  food  would  not  have  been  recov- 
ered. It  is  thus  evident  that  attending  circumstances 
are  often  the  most  important  factors  in  guiding  the 
animal  to  a  consummatory  response. 


194  GENERAL  PSYCHOLOGY 

Judgments  are  influenced  by  temporary  reaction 
tendencies  persisting  from  recent  behavior.  Going 
to  a  funeral  distorts  our  sense  of  humor  for  some 
time  afterward.  The  sentence  a  magistrate  imposes 
on  a  criminal  is  often  partly  determined  by  circum- 
stances attending  the  previous  case.  The  physi- 
cian's diagnosis  is  nearly  always  colored  by  what  he 
has  discovered  concerning  other  patients  recently 
seen. 

We  often  have  a  tendency  to  action  in  the  absence 
of  the  object  whose  manipulation  constitutes  the  act. 
While  dressing  for  dinner,  a  man  may  discover  that 
he  is  without  a  collar  button.  If  neither  shops  nor 
friends  are  at  hand,  and  if  he  is  a  person  of  intelli- 
gence, he  looks  about  him  for  a  substitute  article 
with  which  to  fasten  his  collar.  None  of  the  objects 
that  his  eye  falls  upon  may  seem  suitable  to  him  un- 
til finally  he  discovers  a  paper  clip,  which  he  fashions 
into  a  button.  The  perception  of  an  object  as  some- 
thing that  will  serve  our  purpose  is  a  form  of  judg- 
ment that  may  attain  considerable  subtilty.  The 
perception  of  an  act  as  the  right  thing  to  do  is  a 
judgment  of  much  the  same  kind,  and  successful 
judgments  of  this  sort  characterize  the  highest  de- 
velopment of  behavior. 

A  judgment  may  involve  a  choice  of  alternative 
responses,  as  when  a  player  makes  a  move  in  chess 
or  plays  a  certain  card  rather  than  another.  We 
speak  of  a  situation  as  offering  a  choice  only  when 
two  or  more  response  tendencies  are  approximately 


PERCEPTION  195 

equal.  When  the  conflicting  tendencies  are  of  al- 
most equal  strength,  the  delay  in  judgment  is 
greatest. 

"We  are  conspicuously  lacking  in  judgment  during 
emotional  excitement,  and  this  is  because  the  stress 
of  emotion  renders  unstable  the  equilibrium  of  bal- 
anced reaction  tendencies. 

Judgments  are  often  verbal.  The  word,  which  is 
itself  a  cue  to  response  tendencies,  is  elicited  by  the 
situation  and  serves  to  classify  the  things  we  expe- 
rience. 

Reasoning  is  a  series  of  judgments,  each  consecu- 
tive judgment  resulting  from  the  stimulation  and 
from  the  neural  reorganization  that  the  preceding 
judgment  produces.  As  a  result  of  verbal  reasoning, 
incipient  action  tendencies  may  be  aroused  and  con- 
summated, or  inhibited  and  drained  into  other  re- 
sponse mechanisms. 

Conviction  and  Belief 

Conviction  and  belief  may  be  described  as  the  at- 
tachment of  response  tendencies  to  verbal  state- 
ments that  are  either  heard  or  spoken.  These  re- 
sponse tendencies  may  themselves  be  verbal,  or  they 
may  be  tendencies  to  other  forms  of  behavior,  such 
as  overt  acts  or  emotional  expression.  The  propo- 
sition, " Toadstools  are  poisonous,"  is  believed  when 
we  refuse  to  eat  them,  when  grave  apprehension  fol- 
lows our  having  eaten  them  by  mistake,  when  we  try 


196  GENERAL  PSYCHOLOGY 

to  prevent  our  friends  from  eating  them,  and  when, 
in  response  to  questioning,  we  declare  that  to  eat 
toadstools  will  result  in  illness.  When  any  of  these 
responses  is  diminished  or  absent,  we  say  that  the 
conviction  is  not  complete.  Lower  animals  that 
avoid  eating  toadstools  are  not  said  to  do  so  as  a 
result  of  a  conviction  or  a  belief,  because  their  avoid- 
ance is  not  conditioned  upon  a  verbal  statement. 

We  are  convinced  of  the  truth  of  the  proposition, 
"Influenza  is  contagious,"  if  the  tendency  to  say 
these  words  follows  our  discovery  of  a  supposed  in- 
fluenza case  and  if  this  verbal  response  makes  us 
cautious. 

The  moral  conviction  that  it  is  wrong  to  play  ten- 
nis on  Sunday  consists  first  of  all  in  saying  so  when 
tennis  is  suggested.  Further  than  this,  our  belief 
consists  in  a  tendency  not  to  play,  and  in  displaying 
resentment  toward  those  who  do  such  a  thing.  The 
belief  that  debts  should  be  paid  involves  advocating 
this  statement,  having  a  consequent  tendency  to  pay 
debts,  and  a  show  of  remorse  when  this  tendency  is 
prevented.  When  a  hypocrite  merely  advocates  this 
form  of  honesty  and  does  not  pay  his  debts  and  does 
not  regret  his  failure  to  do  so,  we  recognize  the  in- 
completeness of  his  belief. 

A  belief  may  be  said  to  be  systematized  when  to 
alter  it  would  involve  a  modification  of  many  other 
beliefs,  opinions,  and  habits.  It  is  difficult  for  the 
West  Indian  Negro  to  give  up  his  belief  in  ghosts 
because  many  of  his  convictions  involve  the  word. 


PERCEPTION  197 

His  dead  friends  have  become  ghosts;  many  other- 
wise inexplicable  events  are  caused  by  ghosts;  the 
graveyard  is  awful  because  of  the  presence  of  ghosts ; 
and  the  exact  appearance  and  habits  of  ghosts  have 
been  described  to  him  in  voodoo  teaching.  The  col- 
lege student  may  be  slightly  superstitious  concern- 
ing ghosts,  but,  because  any  such  belief  is  unsyste- 
matized, it  is  easily  dissipated. 

When  a  belief  that  is  unshared  by  the  believer's 
associates  stubbornly  resists  persuasive  argument, 
and  when  it  is  not  the  ordinary  result  of  such  expe- 
riences as  the  believer  has  had,  we  call  the  belief  a 
delusion.  Delusions,  like  other  opinions,  may  be 
systematized  and  emotionally  reenforced,  in  which 
case  they  show  an  obstinate  persistency. 


CHAPTER  VI 

human  motives 
The  Delayed  Reaction 

The  acts  we  perform  to-day  often  seem  to  be  the 
direct  result  of  the  stimuli  we  received  yesterday. 
We  continually  make  plans  for  to-morrow  and  when 
the  time  comes  we  often  carry  out  the  previous  day's 
intention.  Is  this  lapse  of  time  between  the  stimulus 
and  the  reaction  a  true  latent  period  of  response,  or 
is  the  reaction,  when  finally  given,  simply  a  response 
to  sensory  memoranda  furnished  by  our  body  and 
the  external  world?  If  all  our  sense  organs  were 
made  anaesthetic,  could  we  bear  in  mind  the  fact  that 
in  a  little  while  we  must  meet  an  engagement  or  tel- 
ephone to  a  friend?  Would  any  serious  thinking  be 
possible  to  a  person  totally  deprived  of  sensory 
stimuli  and  in  some  way  miraculously  kept  alive? 
Unless  we  find  in  the  laboratory  the  answer  to  such 
questions  as  these,  we  are  in  danger  of  accepting 
some  fanciful  hypotheses  as  to  the  way  in  which 
thinking  proceeds. 

The  central  nervous  system,  while  isolated,  might 
conceivably  be  capable  of  carrying  on  a  self-con- 
tained interplay  of  processes  that  would  result  ulti- 
mately in  an  act,  but  the  fact  remains  that  the  cen- 

198 


HUMAN  MOTIVES  199 

tral  nervous  system  never  is  isolated  from  the  effect 
of  constant  sensory  stimulation.  Even  in  sleep  and 
in  surgical  anaesthesia  the  isolation  from  receptors 
is  only  partial. 

Hunter  constructed  a  choice-reaction  box  that 
had  three  passageways  leading  to  food.1  Any  two 
of  these  passageways  could  be  blocked  and  the  third 
left  open.  The  open  passageway,  varied  at  random, 
was  always  illuminated.  By  trial  and  error,  the  ani- 
mals in  this  box  learned  to  select  the  illuminated 
opening  and  to  avoid  the  others.  An  animal  so 
trained  was  then  placed  in  a  release  compartment 
that  offered  a  view  of  all  three  passageways,  but 
from  which  it  could  not  escape  until  freed  by  the  ex- 
perimenter. The  light  was  turned  on  in  the  open 
passageway  until  it  was  observed  by  the  animal. 
Then,  after  the  light  had  been  turned  off,  an  inter- 
val was  allowed  to  elapse  before  the  release  com- 
partment was  opened.  Even  after  this  delay  the 
animal  could  still  choose  the  correct  exit.  Such  be- 
havior is  generally  referred  to  as  a  delayed  reaction. 
Hunter  found  that  the  interval  between  the  light 
stimulus  and  the  response  could  be  as  long  as  from 
1  to  5  seconds  for  rats,  from  1  to  3  minutes  for  dogs, 
and  more  than  20  minutes  for  a  five-year-old  child. 

Rats,  cats,  and  dogs,  in  order  to  respond  success- 
fully, had  to  maintain  their  orientation  throughout 
the  interval.    This  orientation  preserves  the  stimu- 

i  Hunter,  The  Delayed  Reaction  in  Animals  and  Children,  Animal 
Behavior  Monographs,  1913,  No.  1. 


200  GENERAL  PSYCHOLOGY 

lating  effect  of  the  proper  exit  until  the  animal  is 
released.  The  sight  of  the  closed  barrier  of  the  re- 
lease box  inhibits  the  movements  of  escape.  The 
opening  of  this  barrier  removes  this  inhibition,  and 
furnishes  a  facilitating  stimulus  to  the  escape  move- 
ments that  the  sight  of  the  fixated  passageway  has 
throughout  tended  to  initiate.  The  animal  that 
maintains  its  orientation  throughout  the  interval 
presents  a  picture  of  balanced  reaction  tendencies, 
each  of  which  is  excited  by  a  persistent  stimulus. 
When  one  of  these  stimuli,  namely  the  release  bar- 
rier, ceases  to  act,  the  other,  the  fixated  passageway, 
causes  a  response.  The  situation  that  is  here  at 
work  is  easily  analyzed. 

Children,  even  though  they  had  lost  their  orienta- 
tion during  the  interval,  were  able  to  respond  suc- 
cessfully. Adults  do  this  with  considerable  uniform- 
ity. If  the  person  acting  as  subject  is  carefully  ob- 
served, this  delay  in  reaction  no  longer  seems  to  be 
a  true  latency  of  response. 

The  response  tendency  toward  the  door  last  il- 
luminated would  hardly  have  the  lowest  threshold 
just  because  of  recency  of  excitation,  as  the  other 
doorways  may  be  the  ones  last  looked  at.  When  an 
adult  subject  in  this  experiment  carefully  observes 
his  own  behavior,  one  of  the  following  factors  al- 
ways seems  to  be  present  to  determine  his  correct 
choice.  Sometimes  he  assumes  an  inconspicuous 
orientation,  of  parts  other  than  head  or  eyes,  when 
he  sees  the  light,  and  maintains  this  posture  until 


HUMAN  MOTIVES  201 

the  interval  has  elapsed.  This  serves  as  his  cue 
when  he  is  released.  He  may  guard  against  doing 
this,  however,  with  some  success.  More  frequently, 
his  seeing  the  light  in  a  particular  doorway  is  fol- 
lowed by  some  characteristic  movement  reserved 
for  that  situation,  consisting  of  a  slight  swaying  of 
the  body  or  head,  slight  contraction  of  muscles  on 
one  side  or  the  other,  or  subvocal  speech  movements 
corresponding  to  words  that  designate  the  proper 
doorway.  These  minimal  movements  are  often 
wholly  unobserved  by  the  experimenter.  When  the 
subject  is  released,  a  scrutiny  of  the  doorways  will 
revive  one  of  these  cue  movements,  which  seems  to 
depend  upon  recency  and  upon  the  emotional  reen- 
forcement  characteristic  of  all  preparatory  respon- 
ses, for  its  low  threshold.  This  serves  in  turn  to 
reenforce  the  proper  orientation  and  approach  re- 
sponses. The  subject  usually  reports  that  his  choice 
does  not  depend  on  having  made  merely  the  original 
orientation  movements,  and  when  his  choice  is  cor- 
rect, he  practically  never  fails  to  report  the  occur- 
rence of  some  additional  cue  movement,  sometimes  a 
series  of  such  movements,  that  were  begun  while  the 
orientation  was  still  maintained. 

If  a  stimulus  does  not  cause  an  immediate  re- 
sponse of  one  sort  or  another,  it  will  probably  never 
cause  a  delayed  response  of  any  kind.  If  a  mechan- 
ism is  stimulated  and  the  response  inhibited,  the 
delayed  occurrence  of  the  response,  in  the  absence 
of  the  original  stimulus,  is  due  either  to  a  mainte- 


202  GENERAL  PSYCHOLOGY 

nance  of  orientation  or  to  the  recurrence  of  some 
conditioning  stimulus,  usually  movement-produced. 
Suppose  that  a  man  is  called  to  dinner  while  in 
the  midst  of  work,  and  delays  his  response  until  he 
has  reached  a  convenient  place  for  stopping.  Un- 
less he  changes  his  posture  in  readiness  for  rising 
or  maintains  an  uneasy  tension,  unless  peristalsis 
jogs  his  memory,  or  unless  sounds  from  the  dining 
room  remind  him  that  dinner  is  in  progress,  his  re- 
action is  very  likely  to  remain  delayed  until  he  is 
called  again.  If,  when  dinner  was  first  announced, 
he  happened  to  be  looking  at  the  paperweight  on  his 
desk  as  he  promised  to  be  down  in  a  moment,  a 
casual  glance  at  the  paperweight  might  later  bring 
him  to  his  feet.  Some  sensory  cue  seems  essential 
to  call  out  a  delayed  response  once  the  original 
stimulus  has  ceased  to  act.  Such  a  sensory  cue  may 
be  either  an  organic  stimulus  or  one  external  to  the 
body,  which,  having  occurred  along  with  the  origi- 
nal situation,  has  become  a  substituted  stimulus  for 
the  delayed  response.  Our  environment,  our  daily 
routine,  and  our  rhythmical  bodily  functions  are  full 
of  memoranda  for  these  postponed  reactions.  Lack- 
ing these  helps  we  would  almost  never  carry  out  an 
intention.  Having  made  an  engagement  for  Monday 
morning  we  keep  it  because  the  events  of  Monday, 
when  they  occur,  are  different  from  the  events  of 
Sunday.  No  response  is  ever  given  to  an  abstract 
48  hours  hence.  A  delayed  reaction  is  not  essentially 
different  from  any  other  conditioned  response. 


HUMAN  MOTIVES  203 

The  Wish 

A  wish  is  an  emotionally  facilitated  tendency 
toward  a  consummatory  response  whose  consumma- 
tion is  delayed.  This  delay  may  be  caused  by  the 
inhibiting  action  of  an  antagonistic  mechanism  when 
the  situation  for  carrying  out  the  reaction  is  pres- 
ent. Or  it  may  be  caused  by  the  absence  of  the  sit- 
uation necessary  for  carrying  out  an  act  when  the 
tendency  is  aroused  by  conditioning  stimuli.  Pend- 
ing the  consummation  of  an  act,  the  opportunity  for 
which  is  present  and  interference  with  which  is  ab- 
sent, the  wish  may  be  slightly  in  evidence  while  the 
act  is  being  carried  out.  Thus  we  may  wish  to  take 
a  drink  of  water  while  preparing  to  do  so,  but  this  is 
only  because  the  act  of  securing  the  water  postpones 
the  consummatory  response.  The  other  occasions 
on  which  wishing  for  water  is  evident  are,  first,  when 
water  is  present  and  we  are  inhibited  from  drinking 
by  some  such  circumstance  as  the  presence  of  a 
thirsty  friend,  and,  second,  when  a  dryness  of  the 
throat,  mention  of  water,  or  the  sight  of  an  empty 
glass  prompts  us  to  drink,  and  no  water  is  to  be  had. 
During  the  delay,  in  either  case,  there  is  readily  ap- 
parent the  growing  emotional  reenforcement  that  is 
characteristic  of  the  postponement  of  any  consum- 
matory reaction.  All  wishes  are  consummatory  re- 
sponse tendencies  whose  complete  expression  is  in- 
terfered with,  and  whose  postponement  arouses  emo- 
tional reenforcement. 


204  GENERAL  PSYCHOLOGY 

Attention 

The  several  parts  of  a  situation  do  not  have  equal 
power  at  any  given  moment  to  call  forth  responses. 
A  person  gathering  flowers  picks  some  and  leaves 
others,  or  his  attention  may  be  distracted  by  a  lizard 
on  the  wall.  In  the  theater  we  watch  the  actor  and 
are  oblivious  of  the  audience.  This  is  because  of  the 
differences  in  relative  intensity  of  the  various  stim- 
uli, because  of  the  particular  orientation  of  our  sense 
organs  at  any  moment,  because  of  the  variation  of 
conductivity  in  neural  arcs,  the  result  of  habit  and 
reenforcement,  and  because  of  fatigue. 

Attention  is  the  orientation  of  sense  organs  to- 
ward a  source  of  stimulation  and  the  lowering  of 
appropriate  response  thresholds.  It  always  involves 
more  or  less  preparatory  innervation  of  the  effector 
muscles.  Usually  associated  with  it  is  the  cessation 
of  most  movements  that  do  not  serve  to  explore  the 
object  that  is  attended  to.  Attention  is  most  evi- 
dent when  there  is  a  balancing  of  reaction  tenden- 
cies toward  a  single  object,  as  the  orientation  is  then 
more  persistent  because  the  muscle  contractions  by 
which  the  orientation  is  maintained  are  emotionally 
reenforced.  When  opposing  orientations  are  called 
out  by  two  separate  objects,  attention  to  either  ob- 
ject is  decreased. 

After  a  few  seconds  of  attention  the  muscular 
adjustment  of  the  sense  organ  is  partly  lost,  but, 
because  of  movement-produced  stimuli  that  this  loss 


HUMAN  MOTIVES  205 

occasions,  the  proper  adjustment  may  be  regained. 
Fatigue  also  occurs  in  the  large  muscle  groups  in- 
volved in  orientation,  and  this  has  its  effect  upon  at- 
tention. 

In  addition  to  the  fluctuation  of  muscular  adjust- 
ment, there  is  a  fluctuation  of  conductivity  of  the 
neural  arc,  probably  resulting  from  variation  in  con- 
ductivity of  the  synapses  and  from  the  irregular 
drainage  and  reenforcement  of  the  system.  Thus 
we  always  have  a  sort  of  fluttering  or  pulsation  in 
attention,  even  though  careless  observation  may 
seem  to  indicate  continuous  attention  lasting  sev- 
eral minutes. 

The  movements  of  orientation  may  shift  from  ob- 
ject to  object  following  systematic  or  random 
changes  in  a  situation.  Where  this  shifting  is  pres- 
ent, there  is  likely  to  be  less  fatigue  and  more  emo- 
tional reenforcement  of  the  movements  on  which 
the  orientation  depends.  Attention  to  one  object  or 
to  one  orderly  sequence  of  events  inhibits  responses 
to  unrelated  stimuli,  both  because  of  the  low  thresh- 
olds established  by  the  intense  stimuli  that  result 
from  a  steadfast  orientation  and  because  of  the  facil- 
itation derived  from  many  component  responses  that 
make  up  habitual  acts. 

Volition 

A  voluntary  act  is  the  outcome  of  a  delayed  reac- 
tion when  reenforcement  reduces  a  high  threshold 


206  GENERAL  PSYCHOLOGY 

of  response  or  brings  to  an  end  the  balancing  of  in- 
compatible reaction  tendencies.  This  reenforcement 
is  furnished  by  movement-produced  stimuli  and  by 
external  changes  in  the  environment.  It  is  possible 
that  the  balance  of  tendencies  might  be  lost  and  ac- 
tion result  without  external  coercion,  provided  one 
of  the  two  opposed  reaction  tendencies  fatigues 
sooner  than  the  other.  Introspection,  however, 
usually  detects  either  a  bodily  change  or  a  change  of 
external  stimulation  as  an  antecedent  of  voluntary 
movement. 

We  often  overlook  the  external  changes  that  affect 
our  choice.  We  may  be  undecided  whether  to  take 
the  morning  train  for  a  week-end  vacation.  With 
opposed  tendencies  to  action  mutually  inhibited,  we 
delay  our  decision  to  act,  but  as  the  time  grows  short 
the  balance  is  disturbed,  so  we  pack  our  bag  and 
start.  Here  it  is  the  change  in  the  clock  that  has 
destroyed  the  equilibrium  of  our  hesitation,  although 
we  are  likely  to  credit  ourselves  with  having  made 
an  unaided  choice.  This  disturbance  of  balance  by 
an  external  event  needs  no  lengthy  discussion.  A 
more  interesting  antecedent  of  voluntary  movement 
is  the  balance-destroying  stimuli  that  our  own  bodies 
provide. 

The  opposed  reaction  tendencies  that  are  present 
in  delayed  choice  never  leave  us  wholly  unmoved. 
They  always  bring  about  internal  responses  of  one 
sort  or  another.  The  energy  that  this  opposition 
engenders  is  drained  into  other  systems,  and  pro- 


HUMAN  MOTIVES  207 

duces  either  slight  skeletal  movement  or  various  in- 
ternal changes.  Such  responses  provide  stimuli  that 
are  likely  to  reenforce  one  or  the  other  of  the  bal- 
anced tendencies.  If  enough  reenforcement  is  finally- 
piled  up  on  one  side  to  destroy  the  balance,  a  volun- 
tary act  results. 

Some  of  these  internal  changes  are  difficult  to  ob- 
serve except  introspectively,  and  such  a  method 
never  gives  wholly  accurate  information.  The  res- 
piratory changes  antecedent  to  voluntary  movement 
may  be  graphically  recorded,  and  serve  as  a  good 
illustration  of  balance-destroying  stimuli.  Such  a 
record  is  shown  in  Figure  30.  The  conditions  of  the 
experiment  under  which  this  and  similar  records 
were  secured  are  as  follows : 

The  pneumograph  was  adjusted  at  the  axilla  level. 
The  subjects  selected  were  always  untrained  and 
did  not  suspect  the  purpose  of  the  experiment.  Most 
of  them  did  not  know  that  their  respiration  was  be- 
ing recorded.  Each  of  them  was  seated  before  a 
table  on  which  were  placed  three  small  strips  of 
cardboard.  The  following  instructions  were  then 
given:  "Wait  until  you  feel  that  you  wish  to  do  so, 
then  place  these  strips  of  cardboard  so  that  they 
form  some  geometrical  figure."  The  time  of  the 
first  observable  movement  of  the  subject's  hand  as 
he  reached  for  the  strips  was  indicated  by  the  ex- 
perimenter's closing  a  switch.  A  characteristic  res- 
piratory change,  similar  to  that  shown  in  Figure  30, 
was  observed  in  all  but  one  of  the  12  subjects  em- 


208 


GENERAL  PSYCHOLOGY 


ployed.  These  movements  consisted  of  a  deep  ex- 
piration and  an  inspiration  that  was  interrupted 
by  one  or  more  periods  of  apnoea.  The  initial  hand 
movement  was  executed  only  after  the  apnoea  had 
continued  for  a  brief  moment.     If  the  reader,  pre- 


BEGIN 


5/VO 


FlGUBE  .'30.  RESPIRATORY  ANTECEDENTS  OF  VOLUNTARY  MOVEMENT. 
THE  PROCEDURE  IS  DESCRIBED  IN  THE  TEXT.  VOLUNTARY  HAND  MOVE- 
MENTS OCCURRED  AT  THE  POINTS  MARKED  A  ON  THE  TIME  LINE.  TIME 
IS  INDICATED  IN  5  SECOND  INTERVALS.  THE  FIGURE  IS  TRACED  FROM 
THE  KYMOGRAPH  RECORD.  APNOEA,  FOLLOWING  DEEP  EXPIRA- 
TION,  PRECEDES   THE  VOLUNTARY   MOVEMENTS 

ferably  with  eyes  closed,  will  repeat  for  himself  these 
respiratory  movements,  exhaling  deeply  and  inter- 
rupting his  inspiration  by  several  periods  of  hold- 
ing the  breath,  he  will  be  conscious  of  a  generalized 
innervation  especially  affecting  the  muscles  that  ex- 


HUMAN  MOTIVES  209 

tend  the  arms.  It  is  easy  to  see  how  this  stimula- 
tion from  apnoea  may  so  reenforce  the  reaphing-out 
tendency  as  to  reduce  sufficiently  the  threshold  and 
bring  about  the  act. 

Freedom  of  the  will  does  not  consist  in  our  being 
able  to  perform  either  of  two  incompatible  acts  at 
a  given  moment,  but  consists  rather  in  our  ability 
to  carry  out  an  intention  in  the  face  of  distractions. 
In  popular  speech  the  "strong  willed"  man  is  one 
whose  good  habits  are  sufficiently  well  established  to 
triumph  over  temptation,  but  this  is  an  ethical  class- 
ification. Psychologically,  the  morphine  addict 
shows  an  equal  freedom  of  will  when  he  disregards 
the  remonstrances  of  friends  and  overcomes  the  ob- 
stacles placed  in  his  way  by  the  law. 

Intention 

When,  on  rounding  a  corner,  we  unintentionally 
bump  into  a  stranger,  we  are  unprepared  to  meet 
the  consequences  of  our  act.  When  pushing  him 
out  of  our  way  intentionally,  we  have  not  only  given 
the  precurrent  responses  that  lead  up  to  this  thrust- 
ing him  aside,  but  are  also  prepared  for  defense 
against  his  possible  aggression.  Intention,  like  the 
wish,  is  present  only  when  a  consummatory  response 
is  delayed.  Intention  differs  from  the  wish  in  that 
it  involves  the  actual  presence  of  precurrent  re- 
sponses which,  in  popular  speech,  "commit"  us  to 
the    consummatory    response.      Intention    includes 


210  GENERAL  PSYCHOLOGY 

''making  plans,"  which  is  a  form  of  precurrent 
response.  This  planning  for  an  act  is  not  an  essen- 
tial part  of  the  wish,  because  in  the  wish  there  may 
be  no  precurrent  responses  present.  Planning  often 
takes  the  form  of  verbal  responses  or  modified  move- 
ments of  rehearsal  that  serve  to  adjust  our  behavior 
to  meet  anticipated  difficulties  and  to  facilitate  the 
eonsummatory  reaction.  If,  in  the  past,  we  have 
carried  out  a  eonsummatory  response  in  the  face  of 
familiar  difficulties,  the  total  habit  so  formed  makes 
our  tendencies  to  carry  the  matter  through  a  second 
time  more  an  intention  than  a  wish. 

Drive 

Having  considered  what  kind  of  response  is 
naturally  given  to  each  kind  of  stimulus,  how  new 
stimuli  are  substituted  for  old,  how  responses  are 
integrated  into  new  combinations,  and  how  delayed 
responses  are  finally  brought  about,  there  remains 
the  question  why  some  acts  are  more  persistent 
and  more  energetic  than  others,  why  some  tenden- 
cies are  imperious  and  some  are  easily  discouraged. 
It  is  not  sufficient  to  say  that  a  man's  tendency  to 
act  in  a  particular  way  is  strong  because  he  ' '  wills ' ' 
so  to  act.  Energetic  action  must  be  a  result  of  a 
physiological  mechanism  capable  of  releasing  and 
conducting  the  necessary  amount  of  nervous  im- 
pulse. 

We    cannot    escape    the    hypothesis    that    each 


HUMAN  MOTIVES  211 

stimulus-response  mechanism  has  its  store  of  nerv- 
ous energy,  and  that  nervous  impulses  are  drained 
from  one  mechanism  to  another.  In  this  way 
energy  may  be  borrowed,  and  a  mechanism  that  so 
borrows  it  is  said  to  be  reenforced.  Probably  every 
stimulus-response  mechanism  is  capable  of  action 
without  reenforcement,  but  few  mechanisms  ever 
act  in  isolation. 

The  mechanisms  resulting  in  acts  of  love,  fear, 
rage,  hunger,  pain,  shame,  and  other  emotional 
expressions  are  supplied  with  a  great  amount  of 
latent  energy.  From  these  reservoirs  many  less 
energized  mechanisms  receive  their  additional  drive. 

Any  act  becomes  emotionally  reenforced  once  it 
has  been  elicited  along  with  an  emotional  response, 
the  emotion  becoming  a  conditioned  response  either 
to  the  stimulus  that  causes  the  simple  act  or  to  the 
movement-produced  stimuli  in  which  the  act  results. 

Upon  the  conflict  of  certain  reaction  tendencies 
there  result  such  emotions  as  grief,  anxiety,  shame, 
and  remorse.  The  effect  of  these  asthenic  emo- 
tions is  to  depress  or  inhibit,  rather  than  to  facili- 
tate behavior  in  general.  These  emotions  usually 
arise  when  some  event  has  occurred  that  makes  it 
difficult  or  impossible  for  us  to  carry  out  an  habitual 
consummatory  response.  When  the  death  of  a  baby 
removes  him  from  his  mother's  arms,  the  tendency 
to  fondle  him  is  still  present,  but  can  not  be  ex- 
pressed. If  a  child  breaks  her  doll,  she  is  left  with 
a  futile  tendency  to  play  with  it.    A  man  who  is  put 


212  GENERAL  PSYCHOLOGY 

in  jail  is  inevitably  prevented  from  engaging  in 
most  of  the  consummatory  responses  of  daily  life. 
In  all  these  cases  grief  and  the  depression  of  activity 
result.  If  the  obstacles  to  action  in  these  cases  had 
not  been  insurmountable,  rage,  and  not  grief,  would 
have  been  aroused  and  activity  increased.  The 
utility  of  discouragement  and  melancholy  consists 
in  that  the  victim  of  circumstances  does  not  spend 
himself  in  vain  effort. 

The  internal  changes  involved  in  emotional  re- 
sponses affect  wide  areas  and  bring  about  sustained 
stimulation  to  many  proprioceptors.  The  diffuse 
nature  of  emotional  stimulation  is  easily  observed 
in  anyone  suffering  from  a  toothache  or  in  a  person 
who  is  enraged  or  frightened. 

No  form  of  conduct,  excepting  routine  habit,  is 
persistently  engaged  in  unless  emotionally  reen- 
forced.  Routine  habit  itself  is  originally  estab- 
lished with  the  aid  of  a  borrowed  emotional  drive. 
Dancing,  game  playing,  dangerous  sports,  gossip, 
theater-going,  controversy,  and  business  speculation 
are  energetically  pursued  because  of  the  emotional 
drive  the  situations  arouse.  The  approbation  or 
disapprobation  of  our  fellows  furnishes  to  other- 
wise weak  reaction  tendencies  an  emotional  facilita- 
tion without  which  we  would  never  finish  the  day's 
work. 

Through  social  convention  the  consummatory  re- 
sponses in  such  acts  as  love,  rage,  and  fear  are  often 
inhibited  or  blocked.     During  a  conference  with  a 


HUMAN  MOTIVES  213 

business  enemy  the  preparatory  responses  of  rage 
are  aroused,  but  the  general  situation  inhibits  kill- 
ing. With  the  blocking  of  this  consummatory  reac- 
tion an  ever  increasing  amount  of  dammed  up  en- 
ergy is  provided,  which  finds  outlet  not  in  physical 
violence  but  rather  in  attending  to  business  with  re- 
newed drive.  If  the  competitor  wins  out  in  the  busi- 
ness deal,  however,  this  energy  finds  outlet  in  curses, 
imprecations,  slander,  or  frequently  in  the  fabrica- 
tion of  a  story  that,  when  told  to  friends,  serves  to 
justify  failure  and  to  elicit  sympathy.  After  an  un- 
pleasant ordeal  with  a  business  superior,  a  man  is 
likely  to  talk  to  himself  on  the  way  home,  or  pos- 
sibly later  in  the  evening  to  find  some  excuse  for 
disciplining  the  children. 

The  fascination  of  literary  fiction  is  produced  by 
the  author's  postponing  any  description  of  his  hero's 
consummatory  responses,  and  by  elaborating  his 
preparatory  responses.  By  such  devices  to  secure 
suspense  the  reader's  interest  is  aroused  and  main- 
tained. Always  the  dawn  breaks  and  Scheherazade 
ceases  saying  her  permitted  say  just  as  the  hero  is 
about  to  be  discovered  in  his  hiding  place,  or  while  he 
is  still  in  full  flight.  When  true  love  begins  to  run 
smoothly,  the  story  is  ended. 

Emotional  reenforcement  is  largely  responsible 
for  the  tenacity  of  certain  memories  of  early  child- 
hood. The  situations  thus  remembered  are  nearly 
always  exciting.  Out  of  700  "first  memories"  re- 
cently collected,  more  than  97  per  cent  were  the  re- 


214  GENERAL  PSYCHOLOGY 

suits  of  highly  charged  emotional  experiences.  The 
event  that  leaves  us  unmoved  is  soon  forgotten,  and 
it  is  well  that  this  is  so,  for  an  event's  importance  is 
usually  proportional  to  its  emotional  effect. 

Sublimation 

In  the  laboratory,  when  men  and  girls  are  work- 
ing together,  much  diffuse  and  purposeless  move- 
ment may  be  observed,  which  would  not  occur  in 
other  than  a  coeducational  university.  Properly 
utilized,  this  additional  drive  may  result  in  effective 
work.  The  utilization  of  dammed  up  drive  for  acts 
other  than  the  consummatory  reaction  to  which  it 
would  lead  if  uninhibited  is  called  sublimation. 

When  a  person  becomes  apathetic  toward  his 
work,  he  is  frequently  not  fatigued.  When  this  is 
so,  what  he  needs  is  recreation,  not  rest.  He  may 
go  to  the  theater,  visit  a  friend,  or  play  a  game  of 
cards,  and  then  return  to  his  work  with  new  enthu- 
siasm. This  drive  is  not  so  much  the  result  of  rest 
as  it  is  the  outcome  of  recent  precurrent  emotional 
responses  in  one  form  or  another.  Thus  we  distin- 
guish being  tired  from  being  stale. 

In  the  case  of  children,  when  rage,  love,  or  fear 
behavior  is  initiated  but  blocked,  the  outlet  for  the 
resulting  drive  is  often  in  tears  or  laughter.  Gig- 
gling is  characteristic  of  older  children  under  simi- 
lar conditions,  and  may  be  shown  in  church,  in 
school,  or  anywhere  in  the  presence  of  the  opposite 


HUMAN  MOTIVES  215 

sex.  The  theater  audience  laughs  most  heartily  at 
indelicate  allusions.  Laughter  may  occur  upon  the 
sudden  passing  of  danger  or  upon  the  averting  of  a 
quarrel.  Any  incongruity  in  a  situation  may  cause 
a  blocking  of  emotional  response,  and  this  is  prob- 
ably why  the  incongruous  is  often  whimsical. 

The  sublimated  drive  that  enables  men  to  sur- 
mount obstacles  is  of  various  kinds.  The  competitor 
shows  a  doggedness  of  conduct  that  is  not  found  in 
the  man  who  has  no  rivals.  Love  makes  the  world 
go  round.  ''The  fear  o'  hell's  a  hangman's  whip  to 
haud  the  wretch  in  order."  Many  emotional  states 
are  derived  from  the  basic  elements  of  rage,  love, 
and  fear.  It  is  seldom  that  one  of  these  elements  is 
lacking  when  any  ambition  is  pursued  with  great 
tenacity  of  purpose. 

It  is  necessary  to  recognize  certain  coenotropic 
tendencies  that  may  be  observed  in  all  young  chil- 
dren. Children  seek  opportunities  to  inflict  pain 
on  others,  and  this  inclination  is  called  sadism.  They 
also  tend  in  certain  situations  to  seek  painful  stimuli. 
This  is  known  as  masochism.  They  show  a  propen- 
sity to  exhibit  their  bodies  and,  especially  from  con- 
cealment, to  observe  the  bodies  of  others.  All  these 
tendencies  are  undoubtedly  a  part  of  sex  behavior. 
A  derivative  form  of  the  tendency  to  cause  pain  to 
others  is  seen  in  bossing  and  bullying  other  chil- 
dren, in  teasing  and  in  ridiculing  them,  and  in  com- 
pelling their  submission.  These  acts  borrow  the 
drive  of  the  behavior  from  which  they  originate. 


216  GENERAL  PSYCHOLOGY 

Submitting  to  coercion  may  be  developed  from  the 
more  original  tendency  to  seek  pain.  To  be  con- 
spicuous in  any  way,  as  when  wearing  unusual 
clothes  or  occupying  the  center  of  the  stage,  may  be 
a  modification  of  the  tendency  to  exhibit  the  body. 

As  the  child  grows  older,  his  masterful,  submis- 
sive, and  exhibitionary  tendencies  conform  more  and 
more  to  the  requirements  of  this  world,  and  the 
origin  of  these  tendencies  is  obscured.  Sadism  plays 
its  part  in  taking  people  to  prize  fights,  in  causing 
them  to  read  newspaper  atrocities  or  to  punish  chil- 
dren, and  in  a  more  useful  form  the  same  motive 
gives  drive  to  the  physician,  the  magistrate,  or  the 
army  officer.  Willingness  to  submit  to  pain  makes 
men  tolerant  of  the  imposition  practised  on  them 
by  those  they  love.  Derived  from  exhibitionism  are 
the  acts  of  having  one's  picture  taken,  seeking  news- 
paper publicity,  wearing  lodge  regalia,  crusading  for 
dress  reforms,  speaking  in  public,  or  running  for  po- 
litical office. 

Conflict 

The  blocking  of  a  consummatory  response  ten- 
dency, combined  with  the  absence  of  any  adequate 
outlet  for  the  resulting  emotion,  is  called  a  conflict. 
"When  a  conflict  arouses  an  unusual  amount  of  un- 
liberated  drive,  a  form  of  behavior  known  as  hysteria 
may  result.  The  symptoms  of  hysteria  are  some- 
times shown  in  relatively  futile  acts,  more  or  less 
suggestive  of  the  consummatory  act  that  is  so  well 


HUMAN  MOTIVES  217 

inhibited.  Thus  a  mother  who  has  lost  her  baby  may 
lavish  care  upon  flowers  or  household  pets.  More 
frequently,  however,  the  hysterical  symptom  is  an 
act  that  serves  the  same  purpose  as  the  act  that  is 
inhibited.  For  example,  in  Dr.  Ames'  case,  the  pa- 
tient who  could  not  bring  himself  to  desert  his  wife 
became  hysterically  blind  and  thus  succeeded  in  be- 
ing removed  from  home.  It  should  be  borne  in  mind 
that  the  hysterical  act  or  symptom  is  beyond  the  pa- 
tient's control. 

A  persistent  tendency  to  perform  some  useless, 
silly,  or  distasteful  act  is  called  in  psychiatry  a  fixed 
or  imperative  idea.  This  is  seen  when  a  person  can- 
not avoid  humming  to  himself  a  haunting  melody 
that  has  become  displeasing,  when  the  effort  to  in- 
hibit obscene,  profane,  or  apparently  commonplace 
words  persistently  fails,  or  when  a  distasteful  act 
is  repeatedly  the  final  outcome  of  mutual  inhibition. 
The  reenforcement  that  makes  such  acts  imperative 
is  usually  a  proprioceptive  mechanism,  such  as  sex 
or  anger,  which  has  become  linked  up  with  the  origi- 
nal action  system  through  conditioning.  The  fear 
that  results  from  a  person's  imagining  that  he  is 
becoming  insane  serves  as  such  a  reenforcement,  and 
by  frequent  use  the  fear  of  insanity  increasingly  oc- 
cupies the  mind.  When  the  reenforced  act  is  use- 
ful, and  not  displeasing  to  the  subject,  its  frequent 
occurrence  causes  no  anxiety  and  is  never  thought 
morbid,  although  the  drive  mechanism  may  be  the 
same  as  in  the  case  of  a  fixed  idea. 


218  GENERAL  PSYCHOLOGY 

Forgetting  an  act  may  sometimes  be  due  in  part 
to  the  inhibition  of  tendencies  with  which  the  act 
has  become  associated.2  Our  failure  to  remember 
the  name  of  an  acquaintance  may  be  the  simple  re- 
sult of  long  disuse,  but  if  speaking  the  name  has  be- 
come associated  with  inhibited  action  tendencies,  the 
word  threshold  is  further  raised  and  we  are  often 
powerless  to  recall  the  word. 

Dreams  correspond  to  reaction  tendencies  that  are 
commonly  inhibited  in  waking  life.  In  sleep  the  in- 
hibitions are  partly  removed  by  the  absence  of  cer- 
tain sensory  stimuli  that  affect  us  when  awake.  Re- 
sponses are  prevented  by  the  resistance  in  motor 
conduction  paths. 

Undirected  by  any  very  rich  sensory  experience, 
and  partly  rid  of  inhibitions,  the  imagery  of  dreams 
follows  the  course  of  wish  fulfillment  in  a  way  un- 
known to  waking  thought.  Thus  our  dreams,  when 
properly  interpreted,  reveal  to  us  many  unsuspected 
propensities.  In  this  way  dreams  become  useful 
material  in  the  detection  of  conflicts  in  hysterical 
subjects. 

Overcorrection 

One  of  the  richest  sources  of  the  stimuli  that  in- 
hibit our  responses  is  the  social  sanction  of  our  fel- 
lows. The  world  demands  of  us  many  virtues  we  do 
not  possess.    By  simulating  such  virtues  as  we  lack, 

2  Many  instances  of  such  forgetting  are  described  in  Freud's  Pay- 
chopathology  of  Every  Day  Life. 


HUMAN  MOTIVES  219 

and  so  disguising  our  inmost  tendencies,  we  gain  ap- 
probation and  escape  contempt.  We  ourselves,  how- 
ever, are  never  wholly  deceived  by  the  superficial 
artifices  we  substitute  for  the  more  spontaneous  ten- 
dencies observed  in  others.  In  our  effort  to  con- 
form to  social  standards  we  frequently  overcorrect 
for  our  faults,  so  that  our  virtues  are  too  conspicu- 
ous to  seem  real. 

Persons  who  laugh  loudest  at  the  Saturday  night 
bath  stories  are  likely  to  have  acquired  punctilious 
bathing  habits  late  in  life.  The  genealogical  bore 
is  usually  a  man  of  humble  origin  in  at  least  one  un- 
studied line  of  descent.  Ostentatious  modesty  is  im- 
possible in  anyone  who  is  not  immodest  at  heart. 
A  man  who  subscribes  himself  ilvery  sincerely" 
should  be  watched.  It  is  a  fairly  safe  generalization 
that  the  noisiest  reformers  all  possess  the  tenden- 
cies they  spend  their  lives  in  condemning. 


CHAPTER  VII 


SOCIAL   PSYCHOLOGY 


Social  psychology  deals  with  the  concerted  be- 
havior of  groups  of  individuals,  and  with  the  in- 
dividual's responses  to  his  fellow  man. 

Fellow  Man  as  a  Constant  Situation 

We  pay  more  attention  to  people  than  to  any  other 
part  of  our  environment,  and  they  furnish  the  occa- 
sion for  our  most  elaborate  behavior.  The  com- 
plex variety  of  their  activities  calls  out  in  us  a  cor- 
respondingly rich  assortment  of  responses.  They 
are  not  passive  objects,  but  are  possessed  of  pent 
up  tendencies  to  action  that  may  be  released  at  our 
slightest  intervention. 

Every  culture  presents  to  man  a  distinctive,  pecu- 
liar, and  individual  environment.  An  island  in  the 
South  Seas  has  few  resemblances  to  the  make-up  of 
a  large  city.  The  food,  the  habitation,  and  the  out- 
door life  of  the  Esquimaux  differ  greatly  from  those 
of  the  Louisiana  Negro.  Aside  from  such  universal 
features  of  the  environment  as  light,  atmosphere, 
gravitation,  and  the  uniformity  of  nature,  which 
science  attempts  to  describe,  the  one  thing  common 

220 


SOCIAL  PSYCHOLOGY  221 

to  all  societies  is  fellow  man,  his  anatomy,  and  his 
original  nature.  He  is  fairly  constant  from  one  gen- 
eration to  another  and  fundamentally  the  same  in  all 
localities.  For  this  reason  there  is  an  obvious  fit- 
ness and  propriety  in  the  fact  that,  no  matter  where 
we  may  be  born  or  who  we  may  be,  we  respond  to 
him  with  many  instincts  and  habits  common  to  hu- 
manity. He  has  always  been  the  necessary  object 
when  we  nurse  as  babies  or  love  as  adults.  He  is 
essential  to  our  conversation  and  our  quarrels. 
Without  him  we  could  not  steal,  murder,  or  disturb 
the  peace.  In  his  childhood  he  actuates  us  to  nurse, 
shelter,  and  protect  him.  In  short,  because  of  his 
invariable  structure,  conduct  toward  him  shows  a 
persistent  similarity  in  all  societies. 

Other  Prevalent  Situations 

Gravity,  the  earth's  surface  as  a  dwelling  place, 
rain,  sun,  day,  night,  and  the  seasons,  are  relatively 
changeless  situations  in  the  history  of  the  race. 
Vegetation,  animal  neighbors,  and  the  sources  of 
food,  though  somewhat  the  same  in  every  epoch  and 
every  climate,  show  more  variability.  Houses,  ve- 
hicles, tools,  highways,  industries,  superstitions, 
ceremonies,  recreations,  language,  and  human  in- 
stitutions in  general,  characterize  particular  times 
and  places.  According  as  these  situations  are  gen- 
erally met  with,  a  similarity  of  habits  is  established 
in  all  members  of  society.    The  possession  of  com- 


222  GENERAL  PSYCHOLOGY 

mon  habits  is  what  distinguishes  a  society  from  a 
mere  aggregate  of  people.  It  is  our  task  to  discover 
the  situations  that  accomplish  this  unification  of  re- 
sponse. Although  the  history  of  social  machinery 
is  the  legitimate  subject  matter  of  sociology,  man's 
creation,  acceptance,  and  rejection  of  the  artificial 
forms  of  society  is  a  question  for  psychology. 

People  show  great  similarity  of  behavior  toward 
all  objects  commonly  met  with.  They  sit  in  response 
to  chairs,  sleep  in  beds,  ride  on  trains,  hoard  money, 
distrust  strangers,  and  wear  clothes.  There  are 
other  objects  toward  which  the  world  as  a  whole  does 
not  respond  so  uniformly.  Christians  have  a  par- 
ticular way  of  acting  toward  the  Bible,  Americans 
toward  their  flag,  women  toward  jewelry,  the  voodoo 
worshipper  toward  his  fetish,  certain  groups  toward 
their  totems,  and  each  household  toward  its  belong- 
ings. The  possession  of  similar  response  tendencies 
toward  these  objects  defines  and  unifies  a  group. 

Places,  like  objects,  elicit  characteristic  responses 
in  the  group.  There  is  a  conduct  proper  to  church, 
to  the  dining-room,  the  graveyard,  the  school-room, 
the  ball  park.  Dress  that  is  proper  on  the  bathing 
beach  is  inappropriate  on  the  street  car.  While  in 
a  conveyance  that  moves  vertically  we  remove  our 
hats,  but  when  in  one  that  moves  horizontally  we 
feel  no  compulsion  to  do  so. 

Times,  like  places  and  objects,  stimulate  us  all  to 
common  action.  We  work  by  day  and  sleep  by  night ; 
we  show  good  will  toward  men  on  Christmas  and  ill 


SOCIAL  PSYCHOLOGY  223 

will  on  Hallowe'en;  we  are  boisterous  on  July 
Fourth  and  sedate  on  Sunday.  We  glance  at  the 
clock  and  say  it  is  time  for  the  children  to  be  in  bed, 
or  again  we  say  it  is  time  to  get  up.  There  is  a  usual 
time  for  tea,  vacations,  and  formal  calls.  Birthdays, 
festivals,  weddings,  funerals,  puberty  ceremonies, 
and  harvest  time  all  demand  their  particular  ob- 
servances, and  unconventional  behavior  is  on  such 
occasions  regarded  as  improper. 

We  respond  in  a  characteristic  way  to  people  rec- 
ognized as  belonging  to  certain  classes.  We  reserve 
deference,  affability,  or  generosity  for  some,  and  ar- 
rogance, contempt,  righteous  indignation,  or  fear  for 
others.  Thus  toward  servants,  policemen  in  uni- 
form, royalty,  the  graybearded,  our  betters,  negroes, 
clergymen,  prostitutes,  blood-relatives,  parents, 
criminals,  reds,  radicals,  women,  and  children  we  ac- 
quire distinct  and  conventionally  organized  re- 
sponses. 

The  efficiency  of  words  depends  upon  their  arous- 
ing similar  reactions  in  everyone.  Some  words,  like 
some  places,  objects,  times,  and  classes  of  people, 
provoke  not  only  a  conventional  response  but  arouse 
along  with  it  an  emotional  drive  that  is  particularly 
effective  in  unifying  the  crowd.  The  shrewd  orator 
can  rouse  in  his  audience  shame,  awe,  anger,  pride, 
fear,  or  pity,  by  the  proper  choice  of  words  or 
phrases  or  by  employing  a  particular  tone  of  voice. 
"Americanism,"  "  gentlemanly,"  ''honorable," 
"profiteer,"  "hell,"  are  examples  of  drive-arousing 


224  GENERAL  PSYCHOLOGY 

words.  Titles  are  valued  because  they  command  re- 
spect. "Sir,"  "captain,"  "doctor,"  "professor," 
are  titles  that  often  carry  an  unmerited  prestige. 
Academic  degrees  may  be  sought  as  an  end  in  them- 
selves. Children  hang  their  heads  when  told  that 
they  are  "naughty,"  regardless  of  what  they  have 
done.  Political  catchwords  stir  up  enthusiasm  with- 
out much  dependence  upon  their  literal  significance, 
and  obscene  words  always  secure  the  attention  of 
polite  people. 

Formation  of  Habits  in  Common 

The  formation  of  common  habits  in  a  group  is  due 
to  imitation  and  other  forms  of  conditioned  response 
and  to  adaptation.  Given  the  proper  environment, 
society  as  a  whole  may  form  almost  any  habit  that  it 
is  possible  for  the  individual  to  acquire.  Outland- 
ish customs  are  not  the  fruit  of  anomalies  of  human 
nature  in  strange  peoples,  but  merely  the  growth  of 
a  social  inheritance  guided  by  the  strange  world  in 
which  they  live. 

Properly  regulated  behavior  in  a  community  in- 
volves something  more  than  mere  similarity  of  re- 
sponse among  the  individuals  concerned.  There  is 
always  to  be  found  another  sort  of  unity  of  action, 
which  may  be  called  complementary  behavior.  The 
way  in  which  mother  and  child  secure  best  results 
is  not  to  behave  alike  but  to  behave  differently.  A 
mother  acts  in  much  the  same  way  as  mothers  in  gen- 


SOCIAL  PSYCHOLOGY  225 

eral,  and  a  child  learns  the  way  of  children.  Thus 
commonality  of  behavior  attaches  to  classes  of  per- 
sons, but  the  proper  interplay  of  responses  of  two 
persons  of  different  classes  necessitates  not  similar 
but  reciprocal  conduct.  Indeed,  cooperation  between 
any  two  individuals  demands  complementary  as  well 
as  like  responses.  Officer  and  enlisted  man,  physi- 
cian and  patient,  merchant  and  customer,  master 
and  servant,  teacher  and  pupil,  husband  and  wife, 
lawyer  and  client,  each  acts  according  to  his  con- 
ventional part  in  the  relationship,  but  not  neces- 
sarily in  the  same  way  as  the  person  with  whom  he 
is  holding  social  intercourse. 

Complementary  behavior,  when  it  occurs,  is  the 
inevitable  result  of  the  difference  in  situation  con- 
fronting two  people  who  are  together,  and  of  the  dif- 
ference in  their  nervous  organizations.  For  social 
organization,  it  is  a  happy  fact  that  the  behavior 
the  baby  shows  toward  his  mother  is  useful  in  secur- 
ing him  food,  and  that  the  behavior  he  calls  out  in 
her  is  adjusted  to  the  same  end.  These  are,  how- 
ever, no  more  mysterious  facts  than  is  the  elasticity 
of  the  limbs  of  a  tree  a  mysterious  adjustment  to  its 
successful  spilling  of  the  wind.  When  these  fortu- 
nate reciprocal  relations  occur  in  nature,  they  be- 
come fixed  by  the  preservation  of  the  organisms  that 
show  them. 

In  the  case  of  groups,  as  in  the  case  of  individuals, 
a  habit  response  originally  given  to  one  situation 
may  later  be  given  to  another  situation,  because  of 


226  GENERAL  PSYCHOLOGY 

the  similarity  or  partial  identity  of  the  two.  A  par- 
ent learns  to  discipline  his  child  and  the  child  to  obey 
his  parent,  and  later,  when  the  child  becomes  an 
adult,  this  coercive  and  submissive  relation  persists 
and  is  often  detrimental  to  good  government  in  the 
tribe.  The  "rule  of  the  elders"  in  primitive  cul- 
ture depends  upon  this  undue  pertinacity  of  chil- 
dren's habits  of  obedience  and  parents'  habits  of 
domineering,  and  involves  a  limitation  of  liberty  for 
the  young  and  an  extension  of  privilege  for  the  old. 

The  treatment  of  the  dead  depends  upon  the  per- 
sistence of  habits  formed  toward  the  living.  The 
name,  the  personal  belongings,  and  the  dwelling 
place  of  a  deceased  friend  call  out  responses  that 
are  wholly  inappropriate  when  he  is  gone.  So,  un- 
til these  habitual  responses  of  the  survivors  are  dis- 
sipated, his  ghost  still  walks.  Weapons  are  put  in 
his  coffin  and  food  is  placed  upon  his  grave.  His 
name  is  spoken  with  caution  and  only  his  virtues  are 
mentioned,  lest  he  overhear.  If  he  was  a  headman 
or  chief,  there  still  adheres  to  his  sword  some  of  his 
valor  which  makes  the  weapon  deadly,  and  his  man- 
tle gives  to  his  successor  a  contagious  wisdom. 

The  sentimental  value  of  belongings,  the  attach- 
ment we  show  to  places  in  which  we  have  spent 
happy  days,  the  thrill  aroused  by  the  name  of  some- 
one we  love,  are  all  due  to  the  former  presence  of 
situations  in  which  these  symbols  were  incidental 
features.  The  power  of  the  symbols  to  call  out  these 
conditioned  emotional  responses  makes  men  more 


SOCIAL  PSYCHOLOGY  227 

willing  to  pay  taxes  on  their  homes  and  gives  men  a 
common  interest  in  the  symbolism  of  art,  drama, 
and  fiction.  The  transfer  of  response  to  substituted 
stimuli  may  also  be  due  to  a  mere  similarity  between 
the  new  stimuli  and  the  old.  It  is  hard  for  us  to  mu- 
tilate the  photograph  of  a  friend,  even  though  we 
realize  that  it  is  a  mere  bit  of  paper.  Because 
women  have  learned  to  call  little  children  "cute"  or 
"dear,"  any  object  that  is  a  miniature  duplicate  of 
something  usually  seen  in  large  size  is  apt  to  be  de- 
scribed in  these  words.  We  hear  such  expressions 
as,  "What  a  dear  little  house,"  "What  cute  little 
biscuits."  The  smallest  entry  in  the  dog  show  al- 
ways has  an  attentive  feminine  audience. 

In  childhood  many  responses  are  organized  around 
human  beings  and  are  later  given  to  situations  in 
which  fellow  man  does  not  figure.  Children  learn 
to  seek  their  parents'  protection  when  in  danger,  or 
their  assistance  when  in  trouble.  Parents  and  play- 
mates often  interfere  with  the  children's  undertak- 
ings, and  children  learn  to  overcome  this  interfer- 
ence with  supplicating,  placating,  and  ingratiating 
behavior,  with  plausible  excuses  for  misconduct,  or 
by  sharing  their  possessions  with  these  older  and 
stronger  companions.  To  danger,  pain,  sickness, 
misfortune,  ridicule,  loneliness,  or  failure,  the  child, 
when  he  grows  up,  because  of  the  tenacity  of  early 
habit,  often  responds  in  a  childish  way. 

If  he  is  a  benighted  savage,  he  may  not  realize 
that  sometimes  inanimate  nature  alone  is  respon- 


228  GENERAL  PSYCHOLOGY 

sible  for  his  misfortune,  and,  seeing  no  human  cause 
in  the  situation,  may  make  up  for  its  absence  by  in- 
venting or  by  accepting  as  present  the  evil  spirits, 
demons,  fays,  and  goblins  that  are  part  of  all  savage 
superstition.  These  he  placates  in  childish  fashion 
by  gesture,  cringing  posture,  words  of  praise,  prom- 
ises of  good  conduct,  circumspect  behavior,  and  the 
offering  of  sacrifice.  Because  the  storm  wind  is  de- 
structive he  assumes  it  to  have  a  personality.  The 
dangerous  waterfall,  the  unsealed  mountain,  he 
treats  as  he  would  treat  mighty  human  beings.  When 
plague,  sickness,  drought,  famine,  flood,  shipwreck, 
invasion,  or  other  misfortune  occurs,  the  tribe  as  a 
whole  appeal  to  the  spirits  of  their  ancestors,  or  to 
graven  images  for  the  assistance  that,  as  children, 
they  had  learned  to  expect  from  parents. 

The  combined  appeal  to  the  spirits  is  often  sup- 
posed to  be  answered  by  a  sign  or  augury.  This 
gives  confidence  to  the  idolaters  that  they  will  be 
saved,  and  there  results  such  a  practical  good  as 
the  passing  of  fear  or  the  unification  of  group  effort 
in  meeting  the  misfortune.  This  persistence  of  child- 
ish reactions  in  the  group  makes  fertile  ground  for 
the  growth  of  certain  vocations  connected  with  cere- 
mony, divination,  magic  and  sacrifice.  Thus  there 
are  found  groups  of  professional  conjurers,  magi- 
cians, medicine  men,  priests,  and  augurs  who  select 
and  organize  the  ritual  of  festivals,  incantation  cere- 
monies, and  temple  life. 

In  our  own  civilization  childish  responses  in  the 


SOCIAL  PSYCHOLOGY  229 

face  of  danger  or  misfortune  are  by  no  means  lack- 
ing. The  adult  male,  his  early  tendencies  to  depend 
on  nurse  or  mother  long  overlaid  by  habits  of  prac- 
tical self-reliance,  will,  when  sick  and  taken  to  the 
hospital,  exercise  again  his  infantile  responses.  He 
tolerates  with  considerable  satisfaction  the  personal 
service  of  his  nurse,  querulously  demands  attention, 
is  jealous  of  other  patients,  becomes  fretful  upon 
small  provocation,  and  is  pleased  by  trifles. 

Man  first  shows  generosity  and  kindliness  in  gen- 
eral to  his  family  group  because  his  early  childhood 
is  spent  at  home.  The  attachment  of  these  response 
tendencies  to  the  father,  mother,  brother,  sister- 
situation  makes  it  useful  to  employ  family  names  to 
elicit  these  friendly  responses  toward  society  when 
the  child  becomes  an  adult  and  leaves  his  home. 
Hence  we  have  the  terms  " brother  man,"  "brother 
Elk,"  "little  brown  brother,"  "less  fortunate  sis- 
ter," "sister  republic,"  "mother  church,"  "the 
greatest  mother  of  all,"  "mother  country,"  "father- 
land," "city  fathers,"  "father  of  his  country,"  and 
many  others.  Because  the  husband-wife  relation- 
ship does  not  exist  for  the  child,  these  terms  do  not 
elicit  responses  of  the  sort  just  mentioned,  and  are 
not  found  to  have  this  derived  meaning  in  popular 
speech. 

Language  includes  names  for  many  wholly  mythi- 
cal situations,  and  society  may  react  to  these  names 
as  though  the  situations  were  real.  In  order  to  ex- 
plain the  fact  that  these  situations  fail  to  stimulate 


230  GENERAL  PSYCHOLOGY 

sense  organs,  the  believer  calls  them  immaterial,  dis- 
embodied, incorporeal,  astral,  intangible,  invisible, 
shades,  or  ghostly  shadows,  although  such  words  af- 
ford no  real  explanation.  The  happy  hunting  ground 
and  the  Moslem  paradise  may  conceivably  be  beyond 
the  reach  of  our  sense  organs  because  of  their  great 
distance,  but  it  requires  more  explanation  to  make 
plausible  living  beings  who  may  wrork  good  or  evil 
in  a  physical  world,  but  who  cannot  affect  the  organs 
of  vision  or  touch.  The  ghost  in  the  dark  is  the 
frightened  person's  rationalization  of  his  fright;  the 
evil  spirit  is  the  unfortunate's  rationalization  of  his 
bad  fortune ;  just  as  the  careless  person  explains  the 
loss  of  a  misplaced  article  by  saying  that  a  thief 
must  have  taken  it,  or  just  as  the  farmer  explains 
the  cool  breeze  in  summer  by  saying  that  hail  must 
have  fallen  in  the  vicinity. 

There  is  a  tribe  of  Sioux  in  Manitoba  who  believe 
in  the  existence  of  a  beast  that  has  a  convenient  way 
of  making  itself  invisible  wThen  looked  at.1  Many  In- 
dians have  been  pursued  by  it  along  forest  trails 
after  dusk,  to  fall  exhausted  at  the  outskirts  of  the 
village.  Similar  beings  rattle  tambourines,  write  on 
slates,  move  tables,  and  speak  through  the  lips  of 
mediums.  If  the  credulous  Indian  or  the  devotee 
of  spiritism  is  asked  why  these  odd  beings  do  not 
perform  in  the  sunlight,  he  takes  refuge  in  the  an- 
swer that  it  is  the  nature  of  the  creatures  to  live  in 

i  Reported  by  W.  D.  Wallis. 


SOCIAL  PSYCHOLOGY  231 

darkness.  The  influence  of  unseen  spirits  was  the 
fundamental  doctrine  of  witchcraft ;  it  explained  to 
our  forefathers  the  eccentric  behavior  of  the  insane, 
and  even  now  is  used  by  the  uneducated  to  account 
for  the  tricks  of  the  professional  clairvoyant.  As 
the  Indian's  flight  from  the  noise  in  the  dark  is  ex- 
actly the  same  as  his  flight  would  be  from  such  a 
beast  as  the  tribe  has  talked  about,  a  noise  has  for 
him  all  the  meaning  that  a  real  beast  would  have. 
In  so  far  as  the  old  dupe  gives  the  same  emotional 
response  to  his  dead  son's  name  on  the  lips  of  the 
medium,  or  to  an  alleged  message  written  on  a  slate, 
that  he  would  give  to  the  son's  presence,  the  situa- 
tion seems  real  to  him.  When  we  consider  the  ease 
with  which  an  individual  may  fall  victim  to  a  belief 
in  unrealities,  though  modern  scientific  method  is  at 
his  disposal  for  checking  up  his  belief,  it  is  not  sur- 
prising that,  in  cultures  lacking  the  methods  of 
science,  credulity  for  erroneous  tradition  should  be 
the  rule. 

One  result  of  society's  conforming  to  manners  and 
customs  is  that  thereby  men  are  able  to  react  not  only 
to  what  their  neighbors  have  done  but  also  to  what 
they  are  about  to  do.  This  simplifies  the  world  and 
makes  life  in  communities  possible.  The  amenities 
of  polite  society  expedite  our  taking  leave  of  our 
hostess,  make  ponderous  explanations  of  our  com- 
ings and  goings  unnecessary,  and  prevent  much  of 
the  ill  feeling  that  a  candid  analysis  of  situations 
would  produce.    Similarity  of  custom  produces  soli- 


232  GENERAL  PSYCHOLOGY 

clarity  within  a  social  group.  The  strangeness  of 
contrasting  custom  seen  in  outsiders  emphasizes 
caste  and  prevents  the  cohesion  of  diverse  classes. 

The  Spread  of  Tradition 

Tradition  is  the  whole  body  of  transmitted  direc- 
tions for  dealing  with  situations.  Through  the  in- 
strumentality of  words  we  may  be  properly  prepared 
for  events  that  we  have  not  before  experienced.  Both 
common  sense  and  science  have  this  function,  and 
tell  us  what  to  expect  of  objects  and  people.  Applied 
science  includes  the  description  of  the  effects  of  situ- 
ations on  society.  Knowledge  is  passed  down  to  us 
concerning  what  plants  are  poisonous,  what  to  do 
when  we  wish  to  cross  a  river,  when  to  plant  corn, 
the  way  to  trap  animals,  the  kind  of  weather  that  is 
likely  to  follow  an  east  wind,  or  how  to  insure  good 
luck. 

Morality  consists  of  traditional  directions  for  con- 
duct, reenforced  by  social  coercion.  This  coercion 
is  accomplished  not  only  by  force  but  by  approval 
and  disapproval,  praise  and  censure,  friendliness 
and  hostility.  To  the  expression  in  word  and  action 
of  these  emotions  in  others  we  ourselves  give  emo- 
tional responses.  It  is  these  emotions  in  us  that  con- 
stitute the  drive  toward  moral  conduct. 

Approach  and  avoidance  responses  have  their  an- 
alogues in  the  vocabulary  of  morals;  and  the  words 
good  and  bad,  right  and  wrong,  brave  and  cowardly 


SOCIAL  PSYCHOLOGY  233 

are  stimuli  to  which  we  learn  to  respond  in  early 
childhood.  Although  social  pressure  is  necessary  for 
the  original  establishment  of  morals,  when  the  moral 
habit  is  formed,  it  acts  in  the  absence  of  coercion. 
We  do  not  read  another's  postcard  when  we  are 
alone  because  we  have  learned  to  avoid  doing  so 
while  in  the  presence  of  others.  The  habit  is  re- 
enforced  by  the  words  we  have  heard  applied  to  this 
ungentlemanly  act.  The  student  will  find  many  in- 
teresting examples  of  moral  tradition  and  moral 
habit  in  the  anthropological  literature  concerning 
taboo.  Morals  are  taught  by  anecdote  and  fiction  as 
well  as  by  precepts,  proverbs,  golden  rules,  and  com- 
mandments. The  words  of  the  anecdote  suggest  the 
situation  and  arouse  the  emotions  that  govern  the 
moral  response.  In  this  way  fables  and  stories  be- 
come the  common  heritage  of  society  and  usually  in- 
volve the  ambivalence  of  hero  and  villain. 

Traditions  are  built  up  through  use.  Tem- 
porary fads  in  conduct  are  absorbed  into  the  teach- 
ing of  society  when  they  are  fit,  and  eliminated  when 
unfit.  Even  though  aided  by  this  process  of  selec- 
tion, tradition  is  always  old-fashioned  and  lags  some- 
what behind  practical  needs.  Only  after  words  are 
coined  for  new  predicaments,  and  these  words  have 
wide  acceptance,  is  it  possible  for  tradition  to  oper- 
ate. 

An  individual's  opinion  includes  some  traditions 
but  not  others.  It  also  includes  a  statement  of  facts 
based  upon  his  own  experience.     Thus  opinion  is 


234  GENERAL  PSYCHOLOGY 

built  up  from  suggestion  and  from  induction.  It  is 
usually  impossible  for  the  individual  to  experiment 
in  the  various  sciences,  so  that  he  is  forced  to  de- 
pend upon  the  statements  of  others  for  many  of  his 
views.  Whether  he  accepts  the  unscientific  state- 
ments of  laymen  or  the  conclusions  of  experts  de- 
pends but  little  upon  the  intrinsic  merit  of  their  as- 
sertions. Statements  are  likely  to  be  accepted  that 
reenforce  emotionally  colored  opinions  already  held, 
or  that  are  uttered  in  such  surroundings,  by  such 
persons,  or  in  such  words  as  arouse  reenforcing  emo- 
tions. Acceptance  is  inhibited  when  the  statements 
oppose  existing  beliefs,  or  when  the  situation  in 
which  they  are  heard  arouses  emotional  resistance. 

Thus  individual  opinion  may  include  belief  in  er- 
roneous causes  due  to  the  acceptance  of  tradition 
outside  the  domain  of  science.  In  this  way  supersti- 
tions result  from  the  borrowing  of  opinions.  These 
"idola  theatri"  may  have  widespread  acceptance 
and  pernicious  social  effects.  People  believe  in  the 
unlucky  nature  of  Friday,  or  of  the  number  13 ;  they 
even  accept  the  divine  right  of  kings,  and  the  efficacy 
of  homeopathic  medicines,  of  amulets,  of  rain-mak- 
ing ceremonies,  and  of  "character  analysis." 

When  we  utter  an  opinion,  we  usually  do  so  in  re- 
sponse to  a  listener.  He  may  be  a  friend,  or  an  en- 
emy, a  sweetheart  or  a  rival,  an  employer  or  a  serv- 
ant, a  guest  or  an  insurance  agent.  Our  audience 
may  be  a  crowd  of  one  kind  or  another,  a  congrega- 
tion, a  college  class,  or  a  political  meeting.     The 


SOCIAL  PSYCHOLOGY  235 

words  we  say  are  always  in  part  determined  by  the 
character  of  the  listener. 

What  we  say  is  further  determined  by  the  thresh- 
olds of  our  verbal  response  tendencies.  We  have 
low  thresholds  for  certain  truth  telling  and  for  cer- 
tain lying.  We  have  high  thresholds  for  other  state- 
ments, both  true  and  false.  That  which  "occurs"  to 
us,  whether  it  be  expressed  or  inhibited,  is  a  state- 
ment whose  threshold  is  low.  It  usually  describes 
things  as  we  wish  them  to  be,  and  is  often  designed 
to  elicit  from  society  a  response  that  we  desire.  We 
have  a  low  threshold  for  saying  that  the  runner  of 
the  home  team  is  safe  on  first,  no  matter  whether  this 
is  true  or  false.  The  lonely  child  in  bed  has  a  low 
threshold  for  making  the  statement  that  he  is  thirsty, 
because  this  brings  him  temporary  companionship. 
High  thresholds  attach  to  admitting  that  our  family 
is  of  lowly  origin  or  subject  to  insanity,  to  telling 
our  hostess  that  we  have  had  a  tedious  evening,  or 
to  using  profane  language. 

At  times  customary  inhibitions  to  speech  are  re- 
moved, and  unusual  facilitations  enter  into  the  situa- 
tion. During  a  war,  a  political  campaign,  or  a  class 
conflict,  partisan  feeling  and  hostility  toward  oppo- 
nents drive  us  to  inaccurate  expression  and  weaken 
many  old  inhibitions.  In  his  appeal  to  the  jury  the 
attorney  makes  biased  statements,  and  in  the  heat 
of  eloquence  the  orator  often  garbles  the  truth. 

The  responses  of  the  listener  are  likewise  deter- 
mined by  the  habits  he  has  formed,  as  well  as  by  the 


236  GENERAL  PSYCHOLOGY 

external  situation.  He  has  tendencies  to  accept  some 
statements  and  to  reject  others.  The  tendency  to 
act  upon  or  to  repeat  the  assertions  of  others  is 
called  suggestibility,  and  when  these  assertions  are 
false  it  is  called  credulity.  The  listener,  like  the 
speaker,  is  affected  by  partisan  movements,  and  his 
suggestibility  is  modified  accordingly.  He  is  credu- 
lous of  slander  concerning  political  enemies  and  of 
eulogy  of  his  leaders.  Many  Englishmen,  but  no 
Germans,  believed  a  report  that  St.  George  led  a 
British  detachment  to  victory  in  one  of  the  engage- 
ments of  the  late  war. 

Opinion  Spreads  from  Mouth  to  Mouth 

Where  the  subject  matter  is  outside  the  field  of 
common  sense,  and  thus  not  controlled  by  a  common 
habit  of  statement  in  the  group,  or  where  common 
habits  are  disrupted  by  newly  acquired  social  preju- 
dice, a  statement  of  alleged  fact  undergoes  succes- 
sive modifications  as  it  is  passed  on  from  speaker  to 
speaker.  The  cumulative  error  that  increasingly  at- 
taches to  the  story  is  a  product  of  the  uninhibited 
reaction  tendencies  of  the  successive  narrators.  A 
story  so  embellished  is  called  a  i~umor. 

An  act  can  not  be  imitated  by  anyone  who  has  not 
formed  a  habit  of  acting  in  a  like  way.  Inaccurate 
imitation  results  when  this  habit  is  not  quite  the 
same  as  the  observed  act  that  is  the  stimulus  to  im- 
itation.   This  fact  is  illustrated  by  a  simple  experi- 


SOCIAL  PSYCHOLOGY  237 

ment.  Write  five  digits  such  as  48275  on  a  card. 
Select  a  number  of  subjects  and  have  the  first  one 
copy  the  writing  on  another  card.  Have  the  second 
reproduce  the  copy  made  by  the  first,  the  third  the 
copy  made  by  the  second,  and  so  on  serially  through 
the  group.  The  digits  written  by  the  last  subject  will 
probably  be  48275,  although  the  form  and  size  of  the 
digits  will  be  considerably  altered.  Now  make  a 
nonsense  drawing  of  random  lines  and  have  it  seri- 
ally transcribed  by  the  same  subjects.  A  compari- 
son of  the  original  drawing  with  the  final  transcrip- 
tion will  show  very  little  likeness.  The  reason  that 
the  digits  are  reproduced  throughout  with  fair  ac- 
curacy is  that  all  the  subjects  possess  in  common  the 
habitual  response  of  writing  these  symbols.  The 
cumulative  error  in  the  serial  transcription  of  the 
nonsense  drawing  is  due  to  the  absence  of  any  com- 
mon habit.  The  modification  of  opinion  as  it  is 
passed  from  one  person  to  another  is  greatest  when 
its  expression  is  not  a  common  habit  in  the  group. 
Myth  building  occurs  in  essentially  the  same  way. 
The  myth  grows  as  generations  of  narrators  add  to 
the  account  the  expression  of  their  own  wishes. 
Through  much  addition  and  filtration  its  final  form  is 
a  composite  story  voted  on  by  many  auditors. 

Human  Institutions 

The  foregoing  discussion  has  dealt  chiefly  with 
shared   environments  that  regulate  in   society  be- 


238  GENERAL  PSYCHOLOGY 

havior  that  would  otherwise  be  dispersed  and  unco- 
operative. Original  nature,  as  well  as  a  commonly 
experienced  world,  furnishes  all  men  with  tendencies 
to  act  alike.  Of  these  tendencies,  the  emotional  ex- 
pressions,  depending  only  in  part  upon  training  for 
the  order  and  the  composition  of  their  elements,  are 
the  most  elaborate  of  our  instinctive  behavior  pat- 
terns. Coenotropes  with  emotional  components,  such 
as  flight,  repulsion,  curiosity,  pugnacity,  subjection, 
self-assertion,  parental  care,  reproduction,  gregari- 
ousness,  acquisition,  and  construction,  are  often 
called  "instincts."  Although  they  are  habits  and 
not  instincts,  they  are  acquired  by  everyone  due  to 
the  similarity  of  environment  in  which  all  men  are 
reared.  Given  our  repertoire  of  natural  response 
tendencies  and  a  world  order  such  as  we  have  all 
lived  in,  our  learned  behavior  inevitably  combines 
with  certain  emotional  expressions  to  form  these  al- 
most universally  shared  habit  patterns. 

In  sciences  related  to  psychology  it  is  often  at- 
tempted to  explain  all  human  conduct  in  terms  of  a 
selected  few  of  these  coenotropes.  It  is  then  that  the 
danger  of  giving  the  name  "instincts"  to  these  habit 
patterns  and  the  necessity  of  challenging  such  an 
error  are  made  evident.  Freud's  "Libido,"  Le 
Bon's  "suggestion,"  Tarde's  "imitation,"  Trotter's 
"gregariousness,"  and  Veblen's  "instinct  of  work- 
manship" are  all  conceived  as  vague,  unanalyzed 
forces  that  drive  men  to  action.  Even  when  these 
widespread  habit  patterns  are  correctly  analyzed  and 


SOCIAL  PSYCHOLOGY  239 

clearly  defined,  they  furnish  a  wholly  inadequate  de- 
scription of  human  motives.  They  are  at  best  rough 
and  convenient  terms,  which  we  use  to  portray  con- 
duct, but  each  of  them  applies  to  many  forms  of  con- 
duct of  diverse  origin,  and  all  of  them  taken  together 
fall  short  of  describing  the  majority  of  the  acts  of 
every  day  life. 

Human  institutions  are  social  habits  maintained 
and  directed  by  the  material  equipment  that  is  used 
in  their  exercise.  Banking,  commerce,  manufactur- 
ing, agriculture,  transportation,  education,  slavery, 
marriage,  war,  the  state,  the  church,  the  theater, 
and  the  press,  all  have  their  peculiar  tools,  and  are 
established  not  only  in  custom  but  in  legislation  as 
well.  It  is  futile  to  attempt  a  description  of  the  ori- 
gin and  maintenance  of  any  one  of  these  human  in- 
stitutions in  terms  of  component  instincts,  emotions, 
or  coenotropes.  The  institutions  are  too  complex  to 
permit  such  analysis.  Although  certain  emotions  ob- 
viously predominate  in  some,  emphasis  on  these  pre- 
vailing emotions  is  likely  to  obscure  the  fact  that 
nearly  all  man's  capacities  are  involved  in  each  one. 


APPENDIX 


dh 


APPENDIX 


CONSCIOUSNESS 


When  two  men  are  stung  by  a  bee,  an  observer 
might  describe  both  events  in  the  same  way.  But 
if  the  observer  happens  to  be  one  of  these  two  men, 
he  will  describe  the  two  events  differently.  In  a 
way  this  is  not  surprising,  because  his  eyes  have  wit- 
nessed the  stinging  of  his  fellow  and  his  cutaneous 
sense  organs  have  witnessed  the  stinging  of  him- 
self. Because  those  of  his  sense  organs  affected 
when  he  himself  is  stung  are  different  from  those 
affected  when  another  is  stung,  his  responses  to  the 
two  situations  are  very  dissimilar. 

Almost  any  man  will  say  that  the  description  of 
his  behavior  by  another  overlooks  certain  facts  in 
the  case.  He  will  say  that  he  knows  more  about  the 
events  that  constitute  his  own  life  than  anyone  else 
knows.  And  he  may  say  that  the  difference  between 
being  stung  and  seeing  another  stung  is  not  entirely 
reducible  to  the  difference  in  the  sense  organs  af- 
fected and  the  responses  evoked. 

A  description  of  mind  in  terms  of  stimulation,  neu- 
ral action,  and  responses  is  by  no  means  the  only 
one  in  use.  There  is  another  language,  which  the  in- 
dividual may  employ  in  describing  the  world  as  his 

243 


244  GENERAL  PSYCHOLOGY 

own  experience,  and  which  includes  terms  that  are 
useless  in  a  description  of  behavior.  This  is  the  lan- 
guage of  consciousness,  and  its  importance  is  estab- 
lished by  its  popularity. 

Every  man's  behavior  includes  conversation  about 
his  consciousness,  though  his  consciousness  is  not 
open  to  the  observation  of  others.  In  seeking  in- 
formation about  his  private  consciousness,  he  em- 
ploys the  method  of  introspection,  namely  a  minute 
description  of  his  experience  as  he  knows  it  at  the 
time.  The  introspector  may  report  in  some  such  way 
as  this:  "The  hunger  pang  seems  to  be  located  in 
my  stomach;"  or,  "The  feeling  of  being  about  to 
say  'yes'  involves  less  excitement  than  the  feeling 
of  being  about  to  say  'no'  ";  or,  "I  have  a  clearer 
memory  of  the  visual  appearance  of  digits  than  of 
the  visual  appearance  of  letters." 

Viewed  as  behavior,  introspection  is  usually  made 
up  of  verbal  responses  to  organic  states,  and  these 
responses  are  often  indicative  of  what  is  taking  place 
in  the  body.  The  hunger  pang  is  actually  coincident 
with  a  peristaltic  contraction  of  the  stomach.  The 
consciousness  of  excitement  is  usually  coincident 
with  demonstrable  changes  in  pulse,  respiration,  and 
muscle  tone.  It  is  probable  that  a  clear  imagery  of 
digits  is  coincident  with  cortical  action  correspond- 
ing to  a  part  of  the  cortical  process  that  takes  place 
when  the  digits  are  being  read. 

For  successful  introspection,  the  thresholds  of  the 
verbal  responses  must  be  made  unusually  low  by  ex- 


CONSCIOUSNESS  245 

eluding  distractions  and  by  providing  the  subject 
with  directions  for  self-observation. 


Consciousness  and  the  Nervous  System 

Consciousness  is  supposed  to  occur  only  when  there 
is  nervous  action  in  certain  parts  of  the  cortex.  The 
kind  of  consciousness  that  occurs  depends  upon  the 
part  of  the  cortex  that  is  active.  Destruction  of  the 
visual  cortical  area  results  in  the  loss  of  all  visual 
sensations,  and  destruction  of  other  sensory  areas 
brings  about  a  corresponding  anaesthesia.  Having 
conscious  memories  and  ideas  requires  that  certain 
parts  of  the  cortex  shall  be  intact.  A  decerebrate 
dog  has  presumably  no  sensations,  thoughts,  or  feel- 
ings. 

Sensation 

If  we  analyze  consciousness  into  its  parts,  the  most 
conspicuous  of  these  are  sensations.  We  receive 
a  sensation  of  green  when  looking  at  the  lawn,  a  sen- 
sation of  sour  when  eating  a  pickle,  a  sensation  of 
pain  when  we  burn  our  hand,  and  sensations  of  move- 
ment when  we  walk. 

Sensations  require  the  stimulation  of  sense  or- 
gans and  the  conduction  of  nervous  impulses  to  the 
sensory  areas  of  the  cortex.  Sensations  may  be  di- 
vided into  classes  according  to  the  kind  of  sense  or- 
gans involved.    Thus  we  speak  of  visual  sensations, 


246  GENERAL  PSYCHOLOGY 

auditory  sensations,  or  olfactory  sensations.  They 
may  be  distinguished  also  according  to  their  qual- 
ities. A  color  may  have  such  a  quality  as  red  or 
green.  A  taste  may  have  the  quality  sour  or  bitter. 
Sounds  may  be  high  pitched  or  low  pitched.  Among 
these  qualities  degrees  of  likeness  and  difference  may 
be  distinguished.  Blue  seems  more  like  green  than 
like  red.  Each  different  quality  of  sensation  is  likely 
to  be  accompanied  by  a  characteristic  group  of  re- 
sponses. 

The  qualities  of  tonal  sensations  may  be  ranged  in 
a  continuous  series.  Any  tone  may  be  assigned  a 
place  within  the  pitch  scale,  and  we  can  pass  from 
any  one  pitch  to  any  other  through  imperceptibly 
small  gradations.  Other  sensation  qualities  can  not 
be  arranged  in  such  a  series. 

The  spectrum  arouses  a  series  of  sensations  that 
has  some  resemblance  to  the  pitch  scale,  yet  all  but 
a  few  of  these  sensations  are  analyzable  into  two 
components.  The  only  colors  that  can  not  be  intro- 
spectively  analyzed  are  red,  yellow,  green,  and  blue, 
and  there  is  only  one  pure  red,  one  pure  yellow,  one 
pure  green,  and  one  pure  blue.  Other  colors  seem 
to  have  more  than  one  quality. 

The  unanalyzable  colors  are  sometimes  called 
"physiological"  colors,  because  each  is  supposed  to 
be  the  sensation  resulting  from  a  certain  kind  of 
stimulation  of  a  certain  kind  of  sense  organ.  Almost 
all  people  agree  in  their  identification  of  these  physi- 
ological colors  as  points  in  the  spectral  series.    Any 


CONSCIOUSNESS  247 

deviation  from  these  points  brings  us  to  a  color  that 
seems  to  be  a  mixture  of  two  physiological  colors. 
Thus,  although  we  speak  of  a  series  of  greens  in  the 
spectrum,  these  may  be  divided  into  blue-greens  and 
yellow-greens,  which  lie  on  either  side  of  the  physi- 
ological, or  unanalyzable,  green. 

A  continuous  qualitative  series  free  from  blends 
is  not  possible  in  sensations  of  vision,  odor,  taste, 
touch,  warmth,  cold,  pain,  movement,  or  in  the  or- 
ganic sensations. 

In  the  various  combinations  of  pure  sensation 
found  in  the  consciousness  of  a  given  moment  there 
are  degrees  of  fusion  or  blending.  Two  sensations 
may  so  blend  that  only  careful  introspection  will  an- 
alyze them.  A  note  and  its  octave  sounded  together 
on  tuning  forks,  or  the  touch  and  temperature  stim- 
ulation from  a  cold  metal  object,  give  such  blended 
sensations. 

Two  sensations  occurring  at  the  same  time  may 
fail  to  blend  and  may  appear  quite  separate  and  dis- 
tinct. The  color  and  odor  of  a  flower  do  not  blend, 
though  they  are  experienced  together.  Introspective 
analysis  of  a  sensation  compound  is  possible  only 
when  its  component  sensations  have  been  experi- 
enced separately. 

Sensations  may  combine  not  as  blends  but  in  the 
slightly  less  intimate  association  of  patterns.  Sen- 
sation patterns  are  produced  by  an  aggregation  of 
objectively  separate  stimuli,  such  as  the  parts  of  a 
picture,  or  the  simultaneous  bending  of  many  joints. 


248  GENERAL  PSYCHOLOGY 

The  objective  stimuli  may  also  operate  not  at  the 
same  time  but  in  succession,  as  when  a  melody  is 
played,  a  sentence  uttered,  or  a  golf  stroke  executed. 
Any  combination  of  easily  separable  sensations  that 
is  consciously  felt  to  be  a  whole  is  called  a  pattern. 

Sensations  have  duration,  and  this  corresponds 
roughly  to  the  duration  of  the  stimulus. 

The  intensity  of  sensation  depends  mainly  upon 
the  intensity  of  the  stimulus.  There  is  a  liminal 
threshold  for  sensation  just  as  there  is  for  responses, 
and  the  sensation  does  not  occur  unless  the  stimulus 
is  of  a  certain  intensity.  In  Weber's  law  the  term 
"sensation"  may  be  substituted  for  "response." 

Summation  effects  are  observable  in  sensation  as 
well  as  in  responses,  and  are  brought  about  by  the 
repetition  of  subliminal  stimuli  at  short  intervals.  A 
sound  that  is  too  faint  to  be  heard  when  it  occurs 
once,  may  be  heard  when  it  is  rapidly  repeated  sev- 
eral times. 

Sensations  manifest  initial  torpor.  After  listening 
to  a  watch  we  may  hear  it  at  a  greater  distance  than 
was  originally  possible.  This  is  probably  not  wholly 
the  result  of  a  muscular  adjustment  of  the  sense 
organ. 

Continuous  stimulation  results  in  the  fatigue  of 
sensation,  and  is  greater  in  the  case  of  odor,  taste, 
and  touch  than  in  the  case  of  pain. 

The  threshold  of  sensation  may  be  altered  in  posi- 
tive and  in  negative  adaptation  in  much  the  same  way 
that  the  threshold  of  response  is  modified.    The  in- 


CONSCIOUSNESS  249 

frequent  repetition  of  a  subliminal  stimulus,  that 
is,  one  that  is  not  sufficiently  intense  to  arouse  a  re- 
sponse, raises  the  threshold  for  both  sensation  and 
response.  When  a  stimulus  that  is  above  the  thresh- 
old is  repeated  to  the  point  where  fatigue  interferes 
with  the  response,  both  the  response  threshold  and 
the  sensation  threshold  may  be  raised.  When  a  re- 
sponse threshold  has  been  raised  as  the  result  of 
the  repeated  action  of  an  inhibiting  stimulus,  the 
threshold  of  sensation  will  be  raised  also. 

An  ascetic  is  originally  prevented  from  enjoying 
the  luxuries  of  life  by  the  influence  of  his  austere 
companions.  If  he  remains  an  ascetic,  it  is  because 
one  of  two  things  has  happened.  He  has  either  come 
to  disregard  the  things  of  the  flesh,  in  which  case  he 
develops  negative  adaptation,  both  of  sensation  and 
of  response,  to  these  situations,  or  these  situations 
have  produced  in  him  a  conditioned  response  of  ac- 
tive antagonism,  in  which  case  his  threshold  of  sen- 
sation is  lowered  rather  than  raised. 

Positive  adaptation  of  sensation  always  involves 
positive  adaptation  of  some  response.  This  may  be 
merely  an  increased  tendency  to  orientation.  On  the 
other  hand,  practice  in  responding  to  situations  may 
result  in  a  decreased  intensity  of  sensation.  That  is, 
positive  adaptation  of  response  may  be  accompanied 
by  negative  adaptation  of  sensation.  If  we  have  at- 
tained skill  on  the  typewriter  we  may,  when  writing, 
be  almost  unconscious  of  what  we  are  doing.    This 


250  GENERAL  PSYCHOLOGY 

diminution  of  consciousness  accompanies  freedom 
from  inhibitions. 

Emotion  and  Affection 

Introspective  psychology  has  not  fully  decided  the 
question  whether  emotional  consciousness  can  be 
identified  with  organic  sensations,  the  results  of  in- 
ternal responses.  There  is  a  growing  tendency,  how- 
ever, so  to  regard  them.  Though  essentially  sensa- 
tional, they  may  be  made  up  in  part  of  memories  of 
past  organic  experiences. 

Among  the  affective  states  of  consciousness,  the 
most  generally  recognized  are  pleasure  and  unpleas- 
ure.  These  are  by  some  regarded  as  qualities  of 
sensation,  and  by  others  as  separate  conscious  ele- 
ments. 

Images 

There  is  always  a  short  interval  between  the  stim- 
ulation of  a  sense  organ  and  the  occurrence  of  the 
sensation.  This  time  is  consumed  in  overcoming  in- 
ertia in  the  sense  organ  and  in  the  transmission  of 
the  impulse  from  sense  organ  to  brain,  and  is  known 
as  the  latent  period  of  sensation.  After  the  stimulus 
ceases,  the  sensation  continues  for  a  very  short  time, 
and  this  interval  between  the  end  of  the  stimulus  and 
the  end  of  the  sensation  is  called  the  period  of  lag  of 


CONSCIOUSNESS  251 

the  sensation.  When  strong  stimuli  are  used,  the 
period  of  lag  is  greater  than  the  period  of  latency. 

The  lag  of  sensation  may  be  divided  into  two  parts. 
The  first  is  due  to  the  continued  action  of  the  sense 
organ  after  the  stimulation  has  ceased,  and  is  called 
the  positive  after-image.  A  second  part  following 
this  is  probably  due  to  a  similar  momentum  in  sen- 
sory areas  of  the  brain,  and  is  called  primary  mem- 
ory. This  whole  period  of  lag  may  last  for  but  a  sec- 
ond or  two.  It  accounts  in  part  for  our  ability  to 
distinguish  two  tones  of  almost  the  same  pitch 
sounded  in  quick  succession,  when  this  would  be  im- 
possible if  a  longer  time  intervened  between  the  two. 
It  also  accounts  for  continuous  sensation  from  the 
intermittent  stimulation  of  a  motion  picture. 

After  primary  memory  has  disappeared,  what  is 
known  as  a  memory  image  may  appear  in  conscious- 
ness. Such  images  may  occur  many  years  subse- 
quent to  the  original  sensation.  Some  people  retain 
clear  images  of  childhood  experiences  and  probably 
everyone  has  memory  images  to  a  greater  or  less  ex- 
tent, although  there  are  great  individual  differences 
in  this  kind  of  retention.  In  general,  the  memory 
image  is  clearer  for  recent  experiences,  for  experi- 
ences that  are  novel,  for  experiences  that  are  emo- 
tionally reenforced,  and  for  experiences  that  have 
been  long  continued.  A  day  spent  over  the  micro- 
scope is  usually  followed  by  clear  memory  images  of 
the  material  studied.  We  remember  vividly  an  acci- 
dent or  a  hairbreadth  escape,  our  first  kiss  or  our 


252  GENERAL  PSYCHOLOGY 

first  day  at  school,  the  hospital  room  in  which  we 
spent  two  weeks,  or  the  pocket  knife  we  carried  for 
years.  In  brief,  our  memory  images  are  clear  in  pro- 
portion to  the  recency  and  duration  of  the  original 
experiences  and  in  proportion  to  the  attention  that 
was  given  to  them. 

Memory  images  and  ideas  are  never  wholly 
divorced  from  response  tendencies.  Overt  action 
may  or  may  not  follow  thought,  but  consciousness 
is  most  in  evidence  while  a  response  is  pending.  De- 
layed responses  are  usually  attended  by  a  rich  con- 
scious experience.  When  responses  follow  immedi- 
ately upon  stimulation,  sensations  are  usually 
shorter  lived  and  do  not  wholly  lose  their  initial 
torpor. 

Association  of  Ideas 

Before  the  science  of  behavior  was  developed,  cer- 
tain laws  of  association  were  formulated  to  describe 
the  origin  of  the  sequence  of  ideas.  These  laws  state 
that  in  any  train  of  thought  one  idea  follows  another 
only  when  the  experiences  from  which  these  ideas  re- 
sult have  occurred  in  certain  relationships.  It  was 
shown  that  if  two  experiences  occur  in  immediate 
succession,  the  first,  being  repeated  either  as  a  sen- 
sory experience  or  as  a  memory,  was  capable  of  call- 
ing up  the  other.  "When  we  smell  or  think  of  the 
odor  of  roses,  we  are  reminded  of  their  visual  ap- 
pearance because  roses  have  been  smelled  and  then 
seen  many  times.  When  we  see  lightning  or  even  think 


CONSCIOUSNESS  253 

about  it,  the  idea  of  thunder  is  apt  to  come  to  mind. 
The  law  describing  this  sequence  is  that  of  associa- 
tion by  temporal  contiguity.  The  law  that  describes 
associations  as  due  to  spatial  contiguity  is  reducible 
to  the  first  law.  Objects  experienced  together  in 
space  are  also  experienced  adjacent  in  time.  Even 
where  two  experiences,  though  separated  in  time,  oc- 
cur in  the  same  place  and  are  later  associated,  such 
as  becoming  acquainted  with  two  individuals  on  sepa- 
rate occasions  at  the  house  of  a  friend,  the  matter 
may  be  described  as  a  double  temporal  association. 
Cause  and  effect  become  associated  ideas,  but  only 
when  these  ideas  or  the  experiences  that  underlie 
them  have  been  known  to  us  in  immediate  succes- 
sion. Ideas  that  are  similar  tend  to  arouse  each 
other  because  they  are  partially  identical.  Thus  rats 
may  make  us  think  of  mice  on  account  of  their  similar 
shape  and  odor,  though  the  two  have  never  been  seen 
together;  cigars  may  remind  us  of  cigarettes  be- 
cause both  are  made  of  tobacco ;  red  flowers  may  call 
to  mind  blood.  Some  consecutive  ideas  that  seem 
to  be  associated  on  the  basis  of  their  similarity  show 
a  likeness  that  is  not  so  evidently  an  identity  of  ele- 
ments. There  is,  for  example,  a  similarity  between 
any  musical  note  and  its  octave,  or  between  the  colors 
red  and  violet.  Though  in  these  cases  the  physical 
stimuli  are  far  from  similar,  the  neural  mechanisms 
they  stimulate  are  probably  in  part  identical. 

These  laws  of  association  state  for  ideas  what  the 
conditioned  response  describes  in  behavior. 


254  GENERAL  PSYCHOLOGY 

Cortical  activity  must  underlie  the  apparently  ran- 
dom train  of  thought  found  in  revery  and  dreams. 
It  is  clearly  necessary  that  the  nervous  energy  for 
such  a  chain  of  processes  must  come  from  some- 
where. Is  there  any  reservoir  of  energy  that  is  con- 
stantly available  for  the  maintenance  of  cortical 
processes  in  general? 

The  energy  derived  from  looking  at  a  mutton  chop 
does  not  cause  us  to  think  of  the  logarithm  of  seven 
because  this  decimal  was  never  thought  of  while  the 
mutton  chop  was  in  sight.  The  mutton  chop  does 
not  contribute  energy  to  cortical  processes  that  have 
not  previously  taken  place  while  it  is  being  looked  at. 

There  are,  however,  certain  forms  of  stimulation 
that  are  almost  constantly  present  and,  for  this  rea- 
son, have  in  the  past  accompanied  practically  all  our 
acts  and  all  our  thoughts.  These  are  the  stimuli 
resulting  from  respiration,  heart  beat,  and  the 
muscle  strain  involved  in  maintaining  equilibrium. 
As  these  stimuli  are  almost  always  acting,  every  act 
and  every  thought  is  in  some  degree  conditioned 
upon  them.  Thus  many  cortical  pathways  are  open 
to  these  impulses  and  the  impulses  are  available  to 
maintain  many  trains  of  thought.  An  infrequent 
stimulus,  such  as  the  mutton  chop,  could  energize 
only  a  few  ideas. 

Stimuli  that  are  constantly  present  tend  to  be  fol- 
lowed by  so  many  thoughts  and  responses  that  they 
are  regularly  followed  by  no  one  in  particular,  ex- 
cept, perhaps,  those  that  have  most  recently  occurred 


CONSCIOUSNESS  255 

and  thereby  have  a  low  threshold.  This  may  be  an 
explanation  for  the  tendency  of  recent  thoughts  and 
responses  to  recur  in  the  absence  of  specialized  stim- 
ulation. When  we  go  to  bed,  the  organic  stimuli  that 
have  accompanied  our  conscious  experiences  of  to- 
day are  more  likely  to  revive  memories  of  to-day 
than  memories  of  yesterday,  because  the  thresholds 
of  to-day's  ideas  are  lower  than  those  of  a  time  more 
remote.  Thus  the  imagery  of  dreams  is  of  events  of 
the  day  just  past  and  of  such  events  of  childhood  as 
at  that  time  established  for  themselves  a  perma- 
nently low  threshold.  Thought  is  directed  when  the 
stimuli  that  are  present  have  attached  to  them  only 
a  few  definite  responses.  The  undirected  nature  of 
dreams  and  of  waking  revery  is  to  be  accounted  for 
in  large  part  by  the  absence  of  varied  and  unusual 
stimulation  and  by  the  ever  present  residuum  of  or- 
ganic stimuli. 

That  most  people  are  unable  to  recall  their  dreams 
is  probably  due  to  the  fact  that  few  experiences  of 
waking  life  were  present  during  the  dream  and  so 
cues  for  dream  revival  are  lacking. 

Imagination 

Just  as  two  response  tendencies  may  combine  into 
a  compromise  response  when  simultaneously  aroused, 
so  two  or  more  memories  simultaneously  excited  may 
be  condensed  into  a  resultant  idea,  thought,  concept 
or  notion. 


256  GENERAL  PSYCHOLOGY 

In  imagination  there  come  into  consciousness 
thoughts  and  memory  images  more  or  less  distorted. 
This  sequence  of  imagery  may  seem  wholly  casual 
upon  first  inspection,  but  on  careful  analysis  turns 
out  to  be  determined  first  of  all  by  the  sequence  of 
experiences  of  which  these  memories  are  the 
' '  copies. ' '  No  memory  is  isolated,  but  each  memory 
is  always  introduced  by  either  a  preceding  memory, 
or  a  sensation,  or  a  subliminal  stimulus.  The  image 
follows  such  an  event  because  it,  or  the  past  sense 
experience  to  which  it  corresponds,  has  previously 
followed  this  event. 

The  sequence  of  previous  sense  experiences  is  not 
the  only  factor  in  determining  the  train  of  thought. 
The  train  of  thought  takes  one  direction  at  one  time 
and  another  direction  at  another  time,  because  of 
the  varying  resistance  at  synapses.  In  behavior, 
although  many  responses  are  attached  to  a  single 
stimulus,  usually,  only  one  response  of  lowest  thresh- 
old is  elicited.  In  conscious  thought,  although  any 
idea  has  many  associates,  not  all  possible  asso- 
ciates appear  each  time  the  idea  comes  to  mind.  The 
threshold  of  any  associate  varies  from  time  to  time. 

Attention 

Objectively,  attention  is  the  orientation  of  sense 
organs  toward  the  source  of  stimulation,  the  lower- 
ing of  the  response  threshold,  and  the  cessation  of 
movements  that  do  not  serve  to  explore  the  object 


CONSCIOUSNESS  257 

that  is  attended  to.  Subjectively,  attention  is  the 
dominant  presence  in  consciousness  of  either  a  sense 
experience  or  an  idea,  or  of  a  group  of  sensations 
or  ideas  that  have  a  systematic  relation  to  each  other. 
As  in  the  case  of  behavior,  subjective  attention  in- 
volves the  disregard  of  distracting  stimuli.  The 
clearness  of  attentive  consciousness  that  results  from 
the  absence  of  rivalry  is  often  accompanied  by  sensa- 
tions from  the  muscular  contraction  involved  in 
orientation  and  preparation  for  action.  These  sen- 
sations account  for  the  " effort"  that  seems  to  char- 
acterize the  conscious  state  of  attention. 

The  sensation  or  idea  attended  to  is  determined 
by  the  conductivity  of  rival  pathways  in  the  nervous 
system,  and  by  accompanying  facilitations  and  in- 
hibitions. After  the  lapse  of  a  few  seconds,  a 
sensation  loses  its  intensity  or  an  image  its 
clearness.  This  is  analogous  to  other  forms  of  fa- 
tigue and  invites  description  in  terms  of  increased 
threshold.  After  a  brief  time  the  threshold  is  again 
lowered  and  the  sensation  or  image  may  recur  with 
its  original  clearness.  The  pulse  of  attention  usually 
lasts  less  than  a  second.  Attention  is  most  evident 
when  there  is  a  balancing  of  response  tendencies. 

Perception 

Perception  as  a  conscious  event  may  be  analyzed 
into  two  parts.  On  the  one  hand  there  are  the  sensa- 
tions that  result  from  sense-organ  stimulation,  and, 


258  GENERAL  PSYCHOLOGY 

on  the  other  hand,  there  are  certain  components  that 
are  non-sensory,  but  which  blend  with  the  sensations. 
These  non-sensory  components  correspond  to  mem- 
ory images,  though  they  are  too  well  fused  with  the 
sensations  to  permit  of  easy  analysis.  Herbart  gave 
the  name  apperception  to  the  non-sensory  compo- 
nent of  perception. 

One  of  the  common  errors  of  careless  introspec- 
tion is  to  mistake  the  organic  sensations  of  a  per- 
ceptual response  for  apperception.  When  we  see  a 
snake,  the  sensory  part  of  the  perception  is  by  no 
means  limited  to  visual  sensations,  but  includes  sen- 
sations produced  by  muscular  and  visceral  changes. 

The  Unconscious 

Sometimes  we  are  conscious  of  what  we  are  doing, 
and  sometimes  we  are  not.  When  we  enter  a  strange 
house,  when  we  answer  a  difficult  question,  when  we 
eat  unfamiliar  food,  or  when  we  are  overtaken  on  a 
railroad  trestle  by  an  approaching  train,  we  are  de- 
cidedly conscious  of  the  situation,  if  not  of  the  acts, 
we  perform.  Usually  vivid  memories  of  these  situa- 
tions persist  and  we  are  able  to  describe  the  things 
that  have  happened. 

Consciousness  of  our  own  acts  is  most  likely  to  re- 
sult when  we  are  doing  something  to  ourselves,  and 
are  thus  in  a  position  to  observe  our  own  movements 
and  our  own  bodily  states.  When  a  man  removes 
a  splinter  from  his  own  finger,  tries  on  a  new  suit, 


CONSCIOUSNESS  259 

or  learns  a  new  dance  step,  he  has  a  clear  conscious- 
ness not  only  of  the  external  situation  but  also  of 
what  he  is  doing. 

On  the  other  hand,  a  great  many  situations  and  a 
great  many  acts  do  not  produce  a  state  of  conscious- 
ness. Light  from  a  multitude  of  surrounding  objects 
affects  the  retina,  sounds  stimulate  the  ear,  and  ob- 
jects touch  the  skin,  often  without  our  knowing  any- 
thing about  it,  even  though  they  may  cause  re- 
sponses. Frequently  we  may  take  articles  from  our 
pockets,  or  walk  some  distance  along  a  familiar 
street,  or  draw  diagrams  on  the  wall  of  a  telephone 
booth,  without  being  at  all  conscious  of  acting.  The 
great  majority  of  the  movements  we  make  certainly 
leave  behind  them  no  conscious  memories  and  prob- 
ably arouse  no  consciousness  at  the  time.  Delayed 
responses,  compromise  responses,  and  blocked  emo- 
tional expression  nearly  always  have  a  conscious  ac- 
companiment. In  other  words,  conscious  states  are 
usually  found  when  there  is  interference  among  re- 
sponse tendencies. 

Although  acts  unaccompanied  by  consciousness 
might  well  be  called  unconscious  acts,  the  term,  "the 
unconscious,"  is  generally  reserved  as  a  classifica- 
tion and  as  a  somewhat  too  easy  explanation  for  acts 
whose  lack  of  preceding  conscious  motive,  whose 
lack  of  conscious  accompaniment,  or  whose  lack  of 
resulting  conscious  memory  is  a  matter  of  surprise. 
The  man  who  has  a  horror  of  Gothic  windows  but 
who  does  not  know  why,  is  said  to  have  an  uncon- 


260  GENERAL  PSYCHOLOGY 

scions  motive  for  his  fear.  It  might  possibly  be  dis- 
covered on  investigation  that  as  a  baby  he  strayed 
away  and  was  lost  in  a  gloomy  cathedral,  but  has 
retained  no  conscious  memory  of  this  occurrence. 

Most  of  our  motives  are  unconscious  in  the  sense 
that  we  are  not  aware  of  the  circumstances  under 
which  our  reaction  tendencies  were  established.  We 
are  also  unable  to  say  what  kind  of  emotional  re- 
enforcement  drives  us  to  act  as  we  do.  The  parlor 
maid  who  accidentally  breaks  the  ornate  vase,  the 
dusting  of  which  has  often  caused  her  annoyance,  is 
supposed  by  Freud  to  be  actuated  by  a  subconscious 
motive  in  her  act  of  destruction.  Many  psycholo- 
gists, however,  are  content  to  describe  this  occur- 
rence as  an  awkward  act  resulting  from  the  conflict 
of  two  tendencies,  both  of  which  are  aroused  by  the 
sight  of  the  vase.  One  of  these  is  a  tendency  to  dust 
the  object,  and  the  other  is  a  tendency  to  smash  the 
annoying  thing.  It  is  by  no  means  necessary  to  as- 
sume an  unconscious  mind  that  plots  evil  against  a 
more  righteous  consciousness. 

An  anomalous  lack  of  conscious  accompaniment  is 
seen  in  the  automatic  writing  performed  by  the  hand 
of  an  hysteric.  He  is  unconscious  of  his  act  and  his 
attention  seems  to  be  fully  engaged  on  other  matters. 
This  is  described  as  an  automatism. 

The  absence  of  memory  for  events  that  would 
usually  be  remembered  is  called  amnesia. 


BIBLIOGRAPHY 

Aristotle  : 

De  sensu,  436b. 
Blanton  : 

"Behavior  of  the  Human  Infant,"  Psychological  Re- 
view, 1917,  pp.  456-483. 
Cannon,  W.  B. : 

Bodily  Changes  in  Pain,  Hunger,  Fear,  and  Rage,  New 
York,  1915. 
Colvin,  S.  S. : 

Tlie  Learning  Process,  New  York,  1915. 
Darwin,  Charles: 

The  Expression  of  the  Emotions  in  Man  and  in  Ani- 
mals, New  York,  1892. 
DOLL: 

"Anthropometry  as  an  Aid  to  Mental  Diagnosis,"  Re- 
search Publication  8.     Training  School,  Vineland, 
New  Jersey,  1916. 
Ebbinghaus,  Hermann: 

Memory.    Publications  of  Teachers  College,  Columbia, 
New  York,  1913. 
Goldmark,  Josephine : 

Fatigue  and  Efficiency,  Russell  Sage  Foundation,  1912, 
p.  71. 
Herrick,  C.  J. : 

Introduction  to  Neurology,  Philadelphia,  1915. 
Hill,  Rejall,  and  Thorndike  : 

Practice  in  the  Case  of  Typewriting,  Pedagogical  Semi- 
nar, 1913,  pp.  516-529. 

HOLLINGWORTH,  H.  L.  : 

The  Psychology  of  Functional  Neuroses,  New  York, 
1920. 

261 


262  BIBLIOGRAPHY 

Holmes,  J.  J. : 

Studies  in  Animal  Behavior,  Boston,  1916. 
Hunter,  W.  S. : 

The  Delayed  Reaction  in  Animals  and  Children,  Ani- 
mal Behavior  Monographs,  1913,  No.  1. 
James,  William: 

Principles  of  Psychology,  New  York,  1890. 
Jennings,  H.  S. : 

The  Behavior  of  Lower  Organisms,  New  York,  1906. 
Ladd,  G.  T.,  and  Woodworth,  R.  S. : 

Elements  of  Physiological  Psychology,  New  York,  1911. 
Lashley,  K.  S. : 

' '  A  Simple  Maze ;  with  data  on  the  relation  of  the  dis- 
tribution of  practice  to  the  rate  of  learning,"  Psy- 
choUology,  1918,  pp.  335-367. 
The  Acquisition  of  Skill  in  Archery,  Carnegie  Insti- 
tute, 1915. 
Lyon,  D.  0. : 

Memory  and  the  Learning  Process,  Baltimore,  1917. 
Locke,  John : 

Essay  Concerning  Human  Understanding. 
Meumann,  Ernst: 

Psychology  of  Learning,  New  York,  1913. 
Pechstein,  L.  A. : 

Whole  vs.  Part  Methods  in  Motor  Learning,  Psycho- 
logical Monographs,  1917. 
Peterson  and  Rainey  : 

"Beginnings  of  Mind  in  the  New  Born,"  in  the  Bul- 
letin of  the  Lying-in  Hospital  of  the  City  of  New 
York,  1910. 
Preyer,  W.  T. : 

The  Mind  of  the  Child,  New  York,  1905. 
Pyle  : 

"Economical  Learning,"  Journal  of  Educational  Psy- 
chology, 1913,  pp.  148-158. 


BIBLIOGRAPHY  263 

Pyle  and  Snyder: 

"The  Most  Economical  Unit  far  Committing  to  Mem- 
ory," Journal  of  Educational  Psychology,  1911,  pp. 
133-142. 
Sherrington,  C.  S. : 

The  Integrative  Action  of  the  Nervous  System,  New 
York,  1906. 
Singer,  E.  A.,  Jr.: 

"Mind  as  an  Observable  Object,"  Journal  of  Philoso- 
phy, 1911,  p.  180;  also  1912,  p.  206;  "Consciousness 
and  Behavior, ' '  Journal  of  Philosophy,  1912,  p.  15 ; 
"The  Pulse  of  Life,"  Journal  of  Philosophy,  1914, 
p.  645;  "On  Sensibility,"  Journal  of  Philosophy, 
1917,  p.  337. 
Smith,  Stevenson: 

"The  Limits  of  Educability  in  Paramoecium, "  Jour- 
nal of  Comparative  Neurology  and  Psycliology,  1908, 
p.    503;    "Regulation,"    Journal    of    Philosophy, 
1914. 
Spalding  : 

Nature,  vol.  12,  p.  507. 
Thorndike,  E.  L. : 

Animal  Intelligence,  New  York,  1911. 
Educational  Psychology,  New  York,  1918. 
"Fatigue  in  a  Complex  Function,"  Psychological  Re- 
view, 1914,  pp.  402-407. 
"Notes  on  Practice,  Improvability,  and  the  Curve  of 
Work,"  American  Journal  of  Psychology,  1916,  pp. 
550-565. 
Triplett  : 

"The  Educability  of  the  Perch,"  American  Journal 
of  Psychology,  vol.  2,  p.  419. 
Twitmyer  : 

A  Study  of  the  Knee  Jerk,  Philadelphia,  1902. 


264  BIBLIOGRAPHY 


Watson,  John  B. : 

Psychology  from   the   Standpoint   of   a  Behaviorist, 
Philadelphia,  1919. 
Watson,  John  B.,  and  Rayner: 

"Conditioned  Emotional  Reactions,"  Journal  of  Ex- 
perimental  Psychology,"  1920,  pp.  1-14. 
Wtoodworth,  R.  S. : 

Dynamic  Psychology,  New  York,  1918. 


INDEX 


Act,  44 

Adequate  stimulus,  3 
Adrenal  glands,  37 
Adrenin,  38 
Affection,  250 
Afferent  neurone,  27 
Alimentary  tract,  36 
sense  organs  in,  21 
Ames,  217 
Amnesia,  260 
Apnoea,  208 
Apperception,  258 
Approach      responses,      119  ff, 

142,  232 
Aristotle,  6 

Association  of  ideas,  252 
Associative  inhibition,  99 
Attack,  142 
Attention,  204,  256 
Automatism,  260 
Autonomic  nervous  system,  24, 

see  Fig.  8 
Avoidance  reaction,  118,  119  /, 

142,  232 
Awkwardness,  258 
Axis  of  vision,  8 


Babies,  behavior  of,  139  ff 

Basilar  membrane,  see  Fig.  5 

Behavior,  3 

dependent    on    bodily    struc- 
ture, 3 

Behavioristic      description      of 
mind,  1 

Belief,  195 

Binocular  accommodation,  174 

Blanton,  51 


Blinking,  52 
Blocking,  212,  216 
Brain,  23,  25 


Central  nervous  system,  23 
Cerebral  cortex,  26 
Cerebral  hemispheres,  25 
Chain  reflex,  54  ff,  see  Fig.  13 
Childish   responses,   persistence 

of,  227  ff 
Choice,  194 
Ciliary  muscles,  10 
Cleanliness,  54 
Cochlea,  15,  see  Figs.  4  and  5 
Coenotropes,  134,  238 

definition  of,  137 
Cold  organs,  19 
Cold,  paradoxical,  19 
Cold,  stimulus  to,  19 
Collecting,  138 
Color,  11 
Color  vision,  12 
Colvin,  111 
Common    modes    of    behavior, 

145,  222,  224 
Compromise  responses,  111,  170 
Complementary  behavior,  224 
Conductivity,  5,  205 
Conflict,  216 
Conditioned  response,  88 
Cones  in  retina,  12 
Connecting  neurones,  27 
Consciousness,  1,  243 

and  nervous  system,  245 
Consummatory     response,     60, 
62,  203 

lacking  in  play,  152 


265 


266 


INDEX 


Contiguity,  253 
Convergence,  binocular,  14 
Conviction,  195 
Coordination,  129  / 
Cornea,  8 
Credulity,  236 
Crying,  51 

Cumulative  error,  237 
Curiosity,  156 
Custom,  224,  231 


Darwin,  37 

Dead,  treatment  of,  226 
Delayed  reaction,  198 
Delusion,  197 
Depressing  emotions,  211 
Differential  threshold,  42 
Digestion,  36 
Distance  receptors,  6 
Distraction,  45 
Doll,  140 

Drainage,  97,  99,  211 
Dreams,  218,  255 
Drive,  134,  210  ff 
Dunlap,  104 
Duration,  248 


Ear,  14 

stimuli  to,  15 
Ebbinsjhaus,  105  #" 
Effectors,  3,  5 
Efferent  neurone,  28 
Electric  current,  as  stimulus,  4 
Emotion,  250 
Emotional  expression,  2,  37 

in  infants,  54 
Emotional  reinforcement,  123 

in  play,  153 

in  curiosity,  156 
Emotional      responses,     condi- 
tioned, 91  ff 
Enteric  responses  at  birth,  51 
Enteric  tract,  36 
Equivocal  stimuli,  167,  191 


Events,  perception  of,  161 

Exhibitionism,  215 

Exteroceptors,  6 

Eye,  8 

dark  adapted,  14 
-hand  coordination,  50 
movements,  instinctive,  51 
stimuli  to,  11 

Eyes,  convergence  of,  8 


Facilitation,  44 

by  conditioning  stimuli,  95 
Fatigue,  87,  248 
Fear,  82,  134 

of  darkness,  155 

of  strangers,  154 
Fellow-man,  220,  227 
Fixation,  173 
Fixed  idea,  217 
Following,  131,  143 
Forgetting,   79,   109,  111,  21S, 

see  Fig.  25. 
Fovea,  12 
Free  will,  209 
Freud,  218 
Fusion,  247 

binocular,  14 


Glands,  3 

adrenal,  37 
Goldmark,  87 
Greasiness,  perception  of,  172 


Habit,  inheritance  of,  72 
Hallucination,  168 
Hardness,  perception  of,  171 
Herrick,  102 
Hill,  79 

Hollingworth.  93 
Homesickness,  155 
Hunger,  21 
Hunter,  191 
Hysteria,  216 


INDEX 


267 


Illusion,  168 
Images,  250 
Imagination,  255 
Imitation,  130  f,  163 
Individual  differences,  70  ff 
Inheritance  of  habit,  72 
Inhibition,  45 

associative,  99 

mutual,  40 
Initial  torpor,  85,  248 
Instinct,  48,  136 

classification  of,  60,  64 

definition  of,  48,  145 

transiency  of,  145 
Intelligence  tests,  71 
Intention,  198,  209 
Interoceptors,  6,  20 
Intervention,  responses  of,  33, 
35 

|  Institutions,  239 
Introspection,  244 
Iris,  8 

James,  82,  143 
Jennings,  118 
Judgment,  190^ 

Kinesthetic  organs,  23 
stimulus  to,  23 

Ladd  and  Woodwortb,  8 
Lag,  251 
Language,  162 

acquisition,  132 

in  judgment,  195 

sounds,  51 

subvocal,  162 
Lashley,  79,  89,  116 
Latency,  of  response,  198 
Latent  period,  250 
Laughter,  214 
Learning,  75  ff 

neural  basis  of,  97,  see  Fig. 
19 

whole  vs.  part,  113 


Lens,  8/ 

Liminal  stimulus,  39 
Locke,  90 
Locomotion,  33 
Lyon,  115 

Maintaining  stimuli,  61,  69 

Masochism,  215 

Maturation,  48,  50 

of  premature  infants,  49 

Memorizing,  115 

Memory  image,  251 

Memory  of  childhood,  213 

Mental  tests,  71 

Meumann,  110 

Mind,  243 

Monocular  accommodation,  174 

Motives,  198  ff 

Motor  nerves,  23 

Morality,  232 

Movement     produced     stimuli, 
130,  204,  206 

Muscles,  3 

Muscle   and   tendon   sense   or- 
gans, 23 

Muscles,  involuntary,  24 

Negative  adaptation,  80,  248 

neural  basis  of,  99 
Nervous  impulses,  4 
Nervous  system,  3,  23 
Nest  building,  67 
Neural  arc,  4,  27 
Neurones,  4 

efferent,  27 
Nonsense  syllables,  105 
Nose,  17 
Noise,  182 
Nursing,  56/ 

Observation,  162 

Odor,  sense  organs  of,  17,  see 

_  Fig.  6 
Opinion,  233 
spread  of,  236 


268 


INDEX 


Orientation,  33,  119,  199,  204 
Otoliths,  22 
Overcorrection,   218 
Overlapping       of       responses, 

128  ' 
Overlapping  of  situations,  129, 

161 


Pain  organs,  19 

Pain,  stimulus  to,  20 

Papilla?,  20 

Paramcecium,  117 

Pathwavs,   neural,    23,   29,   see 

Fig.  12 
Patterns,  247 
Pavlow,  89 
Peckham,  59 
Pechstein,  115 
Perception,  15Sj(f,  257 

kinesthetic  and  static,  186 

of  language,  178 

of  objects,  178,  181,  222 

of  occasions,  222 

olfactory,  183 

of  people,  223 

of  places,  222 

of  space,  172  ff,  ISO 

of  time,  187 

touch,  186 
Peripheral  nervous  system,  23, 

see  Fig.  8 
Peristalsis,  36 
Perseveration,  112 
Physical  object,  man  a,  1,  175 
Play,  148  ff 
Pleasure,  250 
Positive   adaptation.   76 /f,   248 

neural  basis  of,  97 
Practice  curve,  see  Fig.  17 
Practice,  distribution  of.  115 

in  serial  response,  105,  106  ff, 
see  Figs.  22  and  23 
Precurrent  responses.  209 

in  play,  153 
Pressure,  as  stimulus,  4 
Primary  memory,  251 


Proprioceptors,  7,  21 
Psychoneuroses,  93 
Pupil,  8 

Puzzle  box,  118,  124  ff 
Pyle,  115 
Pyramidal  tracts,  28 


Quality  of  sensation,  247 


Rage,  37 
Rayner,  91 
Receptors,  3 
Reasoning,  195 

Reenforcement,  emotional,  123 
Reflex,  49 

arc,  28 

arcs  of  higher  level,  49 

conditioned,  89 

grasping,  52 

salivary,  89 

scratch,  30 

time  of,  190 

tongue,  30 
Rejall,  79 
Respiration       and       voluntary 

movement,  125 
Response,  absence  of  utility  in, 
32 

compromise,  46 

conditioned,  88 

delayed  utility  of,  31 

internal,  36 

precurrent,  62,  67,  209 
in  play,  153 

regulatory,    character   of,   5, 
28 

serial,  100  #,  116 
Responses,  incompatible,  100 

overlapping  of,  128 
Right-handedness,  140 
Retina,  8,  11 

fatigue  of,  13 

photochemical  substances  in, 
12 
Rods  in  retina,  12 


INDEX 


269 


Roughness,   pei'ception   of.  171 
Rumor,  236 


Saccule,  22,  see  Fig.  4 
Sadism,  215 

Saving  method,  108,  see.Fig.  24 
Sclerotic,   8 

Semicircular     canals,     21,     see 
Fig.  4 

stimulus  to,  22 
Secretion,  action  on  muscles,  38 
Sensation,  245  ff 
Sense  organs,  3 

classes  of,  6 

position  of,  5 
Sensory  nerves,  23 
Sensorv   neurone,   27,  see  Fig. 

10 
Serial  response,  100  ff,  116 
Sherrington,  6,  9,  46,  102,  22S 
Similarity,  association  by,  227, 

253 
Singer,  2 
Situation,  44,  221 
Skeletal  muscles,  23 
Smiling,  52,  131 
Smith,  30,  120 
Sneezing,  51 
Snyder,  115 
Sociology,  222 
Social  psychology,  220  ff 
Spalding,  139,  143 
Spinal  cord,  23,  25,  see  Fig.  9 

columns  in,  25 
Spirits,  228 
Static  organs,  22 

stimulus  to,  23 
Stereognosis,  172 
Stickiness,  perception  of,  172 
Stimuli,  3 

adequate,  3 

conditioning,  125 

kinds  of,  4 

maintaining,  69 

movement-produced,  55 

proprioceptive,  101 


Stimulus-response     mechanism, 

39 
Stimulus-response   mechanisms, 

interaction  of,  43 
Sublimination,  214 
Suggestibility,  236 
Summation  of  stimuli,  40,  84, 

248 
Summation   of  diverse   stimuli, 

40 
Superstition,  228,  234 
Suspensory  ligament,  9 
Swimming,  not  instinctive,  54 
Symbols,  226 
Synapse,  4,  97 


Taboo,  233 
Taste  and  smell,  20 
Taste  organs,  20 
Taste,  stimuli  to,  20 
Thinking,  1 

subjective  nature  of,  2 
Thirst,  21 

Thorndike,  79,  88,  118 
Thought,  train  of,  253,  256 
Threshold,  76,  119 
Threshold  stimulus,  39 
Throwing,  140 
Tickling,  172 
Timbre,  182 
Time  perception,  187 
Tone,  181 

Touch  corpuscle,  18,  see  Fig.  7 
Touch,  organs  of,  17 
Tradition,  232 
Trial  and  error,  117^ 
Trial    and    error   simplification 

of  responses,  119 
Triplett,  83 

Tvmpanic  membrane,  14 
Twitmyer,  89 


Unconscious,  258 
Utricle,  22,  see  Fig.  4 


270 


INDEX 


Visceral  muscles,  36 

Visual    stimuli,    responses    to, 

134,  142 
Vision,  distant,  11 

double,  14 

near,  11 
Volition,  205 


Walking,  139 
Warmth  organs,  18 


Warmth,  stimulus  to,  19 

Wasp,  59 

Watson,  50,  54,  89,  91, 134,  141 

Weber's  law,  42,  248 

Wetness,  perception  of,  171 

Wilson,  112 

Wish,  203 

Wish,  fulfillment,  218 


Yawning,  51 


(l) 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 


Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 


M    8  1956 

MAR1^>  1957 

MAK  2  9  1957 

JFC9    L 

BeA0'57LF 


WAY     8 


R  3    C 


7 
SUMMER 


MAY  1 9  1864 


a    RECD 


JUL  19  REC'D-SAM 


MAR     11967 
pEB  1 6  RECD  -l 


DEC  ; 
NOV  30  RECD  -6 


DURING 
SESSIONS 


PM 


F'H 


LD  21-95m-ll,'50(2877sl6)476 


LLC  BERKELEY  LIBRARIES 


CDSTMflb^Mfl 


